Hey everyone, Xethik here with some FAQ overviews. Please note that these are my opinions, and are not more "correct" or worth more than anyone elses. You can kind the new Grey Knight FAQ here and the new rulebook FAQ here. The quotes will be in italics.

ERRATA
Page 87 – Ordo Malleus, Hereticus and Xenos
Inquisitors, Options, last bullet point
Change to “[...]psychic power. He may exchange any
one weapon for a force sword[...]”
Page 96 – Weapons, Unholy Gaze
Change the AP value from “-” to “4”

Well, what does this change? It means you can choose to take a weapon upgrade for your Inquisitor and purchasing a psychic power, if you would like. Very nice if you are looking to equip Daemonswords or the such and take Hammerhand without losing a pistol or other shooting weapon.
The change in the AP Value of Unholy Gaze seems to have been a mistake from within the codex to the last reference page. Nothing too big.

Q: A psyker can use one psychic power per Mastery
Level, per turn. Is this per player turn? (p21)
A: Yes, otherwise it would state per game turn. 

Just a small clarification. This is always true but is a common FAQ question.

Q: What counts as a Daemon? (p21)
A: Everything in the Chaos Daemons codex, Daemon
Princes, Possessed Chaos Space Marines, Obliterators,
summoned greater Daemons, summoned lesser
Daemons, any vehicle with the daemonic possesion
upgrade, Daemonhosts, Mandrakes, Kheradruakh the
Decapitator, the Avatar.

 This is huge. Really nice to see what is and isn't a Daemon. I mean, sure Daemon Princes seemed obvious, but without this FAQ I probably would not be using Preferred Enemy against them. I feel bad, as it is not if Chaos needs more incentive to avoid Grey Knights.

Q: If a walker is the target of Unyielding Anvil, from
the Grand Strategy special rule, can it claim objectives
even though it is a vehicle? (p22)
A: Yes.

Honestly, I thought the wording to claim objectives as if it was a troop was intentional to not let walkers score. I guess I was wrong. Can be really nice to throw Unyielding Anvil onto Dreadnoughts with Autocannons to hold those rear objectives.

Q: If a unit is the target of Unyielding Anvil, from the
Grand Strategy special rule, and it splits into combat
squads, can both combat squads claim objectives? (p22)
A: Yes.

I believe (and have been playing) as if all Grand Strategy powers affect both parts of the combat squad. Seems to be the logical way to play it, not sure why this question came up.

Q: If a Grand Master gives a unit with personal
teleporters the Scouts special rule, can they use the
shunt move as a part of their Scouts move? (p22)
A: No.

I know this was a very debatable matter and it seems to have gone the way I think most of us expected. It works with the wording best, I think, and it most fair.

Q: Can vehicles benefit from the effect of The
Shrouding psychic power if they are in range? (p25)
A: Yes.

Not sure why this was a question, really. I don't know why they wouldn't other than it makes the power VERY strong. Which it is already.

Q: Personal teleporters make the unit with them jump
infantry. How does this affect a Dreadknight with a
personal teleporter? (p28)
A: It is a monstrous creature that moves like jump
infantry.

Expected and well worth the addressing. I don't think I would want any player arguing Dreadknights in Storm Ravens or them losing 2d6 to pen vehicles, so I'm just glad they got rid of the capability to.

Q: Wounds caused by a Purgation Squad after using
their Astral Aim psychic power get an unmodifiable 4+
cover save. Can these be taken against Wounds caused
by incinerators? (p29)
A: No, as they ignore cover saves.

Makes sense. Not modifying the given cover save, just ignoring it.

Q: What effect does the Cleansing Flame psychic power
have on vehicles? (p31)
A: None, as vehicles can’t be wounded.

Darn, still can't wound vehicles.

Q. Taking Inquisitor Coteaz in your force turns
Henchman Warbands into troops choices. Does this
mean that they take up a force organisation slot and
can no longer be taken as an elites choice? (p33)
A. Yes to both questions.

I don't care if you can argue this as a rule change, it was a needed and expected one.

Q: Does a Dreadknight with a Nemesis doomfist strike
at Strength 6 or Strength 10 in close combat? (p34)
A: Strength 6, as it is not a walker.

Huh. I figured that was an oversight on GW's part, but I guess it was intentional, but they wanted to give Dreadnoughts and Dreadknights the same weapon, so they wouldn't have to come up with two different names.

Q: Does a Dreadknight armed with two Nemesis
doomfists get an extra attack in close combat? (p34)
A: Yes.

Again, not sure where confusion arised, but at least they answered it logically.

Q: Can Brother-Captain Stern use his Zone of
Banishment psychic power if he is not engaged in
combat? (p41)
A: No.

Not like Stern receives much love, anyway. Not a huge change, but worth the clarification. Guess you can't suicide Deep Strike him to victory.

Q: If Justicar Thawn is dead at the end of a game
involving kill points, does he only give away one kill
point regardless of how many times he was killed?
(p43)
A: Yes. It is also worth noting that if he does come
back, he is treated as a seperate unit from that point
on and as such both he and his unit will eachbe worth
a kill point.

 GW, did you spell separate wrong?! My god! I mean, missing a space is acceptable, but man... Oh right. Well, this doesn't come off a surprise. Dead units are kill points. Got it.

Q: When are the shooting attacks from Inquisitor
Coteaz’s I’ve Been Expecting You special rule fired?
(p45)
A: They are fired as soon as a unit that is a valid target
is placed on the board. Once the shooting attacks have
been resolved, the unit can complete its move. If the
unit is arriving by Deep Strike, this will be after the
scatter has been resolved.

So I can't kill Necrons off of the board to stop them from We'll Be Back-ing? And I can't kill transports off the table and kill their squads? Darn.

Q: Does a squad disembarking from a Drop Pod, or
Mycetic Spore, count as arriving from reserve for
Inquisitor Coteaz’s I’ve Been Expecting You special rule?
(p45)
A: Yes, this means that Inquisitor Coteaz and his unit
will be able to fire once at each unit.

I believe this is how Mystics worked, so not much a surprise.

Q: Will Inquisitorial Servitors in a squad without an
Inquisitor that has been joined by a Techmarine still
suffer from Mindlock? (p49)
A: Yes, Inquisitorial Servitors are linked to Inquisitors
and not Techmarines.

Sure, it doesn't make a large amount of sense, but they are the rules, clearly stated in the book.

Q: For each Jokaero Weaponsmith in a henchman unit
after the first you add +1 to the Inconceivable
Customisation roll. Does this mean that if you have 6 or
more Jokaero in a unit that they will receive no
bonuses (as you cannot roll less than a 6 and duplicate
rolls are ignored)? (p50)
A: Yes.

Goodbye gorilla armies! Actually, this has been the way it has been played and I think most people would hope it would be changed. I guess not...

Q: Can models in Terminator armour embark onto an
Inquisitorial Chimera? (p51)
A: Yes.

 This has always been the case in 3rd/4th/5th edition, so not really a surprise. Counts as two occupants, still.

Q: If a Callidus Assassin chooses a unit of vehicles as its
target for its Polymorphine special rule what facing is
hit? (p53)
A: You can choose which facing is hit, but the Callidus
Assassin must then be placed within 3" of the vehicle,
and in the arc of the facing that was hit.

 Glad they clarified that. Well worth answering, though I'm not sure how often I will be worrying about it.

Q: If the unit targeted by a Callidus Assassin’s
Polymorphine special rule is wiped out by it, where is
the Assassin placed? (p53)
A: Within 3" of where the unit used to be.

I was wondering about this and I figured you could always place it within 3" of models of the unit, even if they were just removed. That wasn't clarified, however. (For example, you kill all but one model. Do you have to be within 3" of that one model or can you be where the other models died?)

Q: If a model with a Nemsesis force halberd has had his
Initiative reduced to a fixed number by an
ability/special rule, do they still get the +2 Initiative
from the Halberd? (p54)
A: No.

Not much of a surprise. Initiative 1 means Initiative 1, even with a fancy weapon.

Q: Do Nemesis falchions count as 2 close combat
weapons and thus give +2 Attacks in close combat (+1
for their special rule and +1 for wielding 2 close
combat weapons)? (p54)
A: No, they just give +1 Attack.

Saw this coming, sadly. I don't think they will be worth it with only one attack, as they were barely worth it with two attacks.

Q: If an Ordo Malleus Inquisitor takes 2 Daemonblades
how is this resolved? (p56)
A: Roll seperately on the table for each Daemonblade.
He will gain the effects of whichever Daemonblade he
uses in that round of combat.

I think this is pretty much said this in the rules. I may have mentioned this in an earlier post...

Q: How do you work out whether a psyker is affected
by the Psi-shock special rule on a mindstrike missile or
a psyk-out bomb? (57, 58)
A: Any psyker under the template will be effected by
Psi-shock.

Ouch. Means you can't 'wound allocate' out of  Perils, but that was expected as it is worded this way. Either way, going to do major damage to enemy Grey Knights and Eldar (some others, too).

Q: Does the entire unit need to be equipped with rad,
psyk-out and/or psychotroke grenades for their effects
to work or is just one model being equiped with them
enough? (p60)
A: One model in a unit is enough.

 If this wasn't the case, there would be very little point in taking them...

Q: Are units with either the Stubborn or Mob Rule!
special rules effected by the ‘They’re horrible’ result of
the psychotroke grenade? (p60)
A: Yes, such units will be reduced to Leadership 2.
However a unit with the Mob Rule! special rule that
has 11 or more models will still be Fearless.

Didn't see affecting Stubborn units coming. Makes Psychotroke Grenades even better.

Q: Do you take into account the strength increase from
the psybolt and psyflame ammunition vehicle upgrades
when working out if a weapon is a defensive weapon
or not? If a vehicle has either of these upgrades, must
you use them? (p62)
A: Yes to both questions.

Obviously, a penalty to such things like Land Raider Crusaders, but one that makes sense. Sorry, you can't cheat out of it.

Q: Does the effect of servo-skulls stack? For example
would it reduce the scatter distance by 2D6 if you are
within 12" of two? (p62)
A: No, it would still only be 1D6.

No, you still can't cheat that hard, sorry. Fits the wording, too, so can't complain of a "rule change" here.

Q: Would an orbital strike relay targeted within 12" of
one or more servo-skulls have its scatter distance
reduced? (p62)
A: No, it always scatters the full 2D6".

I know many were hoping this wasn't the case, but it does say the "full 2D6" " right in the entry. Bit disappointing, though.

Q: Does an enemy unit arriving by deep strike or
deploying within 6" of a servo-skull count as moving
to within 6" of it? (p62)
A: Yes, remove the servo-skull from play.

Darn. Having the Servoskulls next to where your enemy was deploying sounded like a lot of fun.

Q: What counts as a plasma weapon for the Ulumeathi
Plasma Syphon? (p62)
A: All Plasma weapons, as well as Eldar missile
launchers firing plasma missiles, burst cannons,
starcannons, all Tau pulse weapons and any weapon
described as using ‘plasma’ as its effect or in its special
rules.

Wow, that affects a lot. Not sure many people who plan on using these things, anyway. They are kind of a cool and interesting piece of wargear, just not very useful... Except against Tau.

Q: Can you only take an Inquisitorial henchmen
warband if you have an Inquisitor in your army? (p90)
A: Yes, you can take a maximum of one warband for
each Inquisitor (unless you take Inquisitor Coteaz).

I know a lot of people were trying to say you could take Henchmen as an Elites choice without an Inquisitor, but this obviously isn't the case.

Q: Are Wounds from Dangerous Terrain tests allocated
in the same way as shooting attacks? (p14)
A: No. Each model moving through dangerous terrain
must take a test. Each model that fails takes a Wound.

Makes sense, in a wound allocation sense, but now dangerous terrain will be really obnoxious to roll against with very diverse squads. No big deal, I guess, though.

Q: How does Rending work if you get to roll multiple
dice for the Armour Penetration roll? (p31)
A: The player gets to add a D3 to the total for each
dice that comes up with a 6.

Not sure how this works unless somehow you have a 2D6 roll for armour pen but have been reduced to Strength 2 (perhaps by grenades, etc) as S 3 + 12 (from the double pens) would pen anything, as would S2 + 12 + 1 (minimum value for one rend). Anyone have a good idea?

Q: Can a model equipped with multiple grenades use
all of them in the same Assault phase? (p36)
A: Yes.

Huh. Interesting, I guess. Throwing Kraks and Meltas at the same time onto vehicles, perhaps. Depends on how people argue it. It was definitely intended for Frags and Psyk-Outs and Rad, which I've never thought using all of them was wrong, but I'm not sure if they intend for multiple offensive grenades to be used on vehicles.

Q: Do the effects of the same psychic power cast
multiple times on the same unit stack? (p50)
A: Yes, unless specifically stated otherwise.

I'm going to admit I thought the opposite ruling would occur. Wow. Hammerhand stacking much? Grey Knight Techmarines + 2 HQs in one super-duper Deathstar. Who needs Daemonhammers for Strength 10?!

Q: Can a psyker attempt to cast the same psychic
power more than once in a turn? (p50)
A: No, unless the psychic power itself specifically allows
it.

I could have sworn this was already a rule, for whatever dumb reason, and I've been playing this way for whatever reason. I guess the Eldar codex fooled me, a bit.

Q: What psychic powers count as psychic shooting
attacks? (p50)
A: Any psychic power with a profile like that of a
ranged weapon (i.e. has a range, strength and AP
value) and any psychic power that specifically states
that it is a psychic shooting attack.

Okay. Nothing big here. Though I believe this means a lot of powers you would think are (and I believe under previous wordings were) psychic shooting attacks now aren't. I'll confirm and comment later.

Q: Do psychic shooting attacks need to roll to hit? (p50)
A: Yes.

Before Tyranid players flip out, I'm pretty sure (could be wrong, haven't checked yet) that all Hive Tyrant powers automatically hit. Jaws will be pretty odd if it doesn't automatically hit, as will several other powers. We'll see what happens.

That seems to wrap things up, everyone. Feel free to comment away! Hope you enjoyed.
Xethik