So, first, the setup ..."He picks up his staff and helmet." - This was the last listed action Cookie made. This means two things: a) he hasn't actually donned the helmet yet, it is a held item, and b) he hasn't gone yet this first round, so no AOOs from him.
Also, if he is holding both the staff and the helmet, that means the staff is held in one hand ... and therefore does not offer bonuses as a two-handed weapon for the purposes of disarming. Also, the helm of brilliance is not a melee weapon, so that will be a penalty for him as well.
I am referencing the following in having set up my actions:
Disarm & Grabbing Items.
FA: Quicken SLA [mirror image], Images = [roll0], max 8
FA: Begin flying, but without moving anywhere. Since no height is gained, this is assumed to be no different than a 5' free move, even though his actual position didn't change 5'.
FAA: Because I don't want to hold people up with my "first attack" post, your resolution, my "second attack" post, etc. Here is what I want to do, and I continue on each action until success, and then move on to the next item:
1) Disarm/ Grabbing Items maneuver to grab
helmet of brilliance.
* Lok's size advantage (+4) is cancelled out by his use of natural weapons (-4).
* Cookie suffers an
overall -4 penalty to his roll to keep from being disarmed, since the helmet is not a melee weapon.
2) Whether he grabs with claws, beak, or talons, the second objective is to snatch away the
staff of the magi.
* Same cancellation applies for Lok's size/natural weapons.
* Cookie does not suffer the -4 penalty since a staff is a melee weapon. However, holding it in one hand he doesn't gain the +4 bonus, either. So,
overall Cookie has no modifier(+0) in keeping from having the staff disarmed.
3) If Lok has any attacks left over, use them to trip Cookie to keep him from trying to follow into the portal. Not that there's really any place for it in D&D, but having a large fat man on the floor might prove an impediment for anyone else coming in. Lok gets a +4 on Trip attempts for size. Size of weapon (i.e., light weapon) is immaterial on a trip. Cookie avoids with a straight-up Strength or Dexterity roll.
4) If Lok scored perfectly ... that is, first claw took helmet, second claw took staff, and beak tripped Cookie, then the talons will be used to tear at the fallen man.
Attack 1 (Disarm, Claw 1): [roll1]
Attack 2 (Disarm, Claw 2): [roll2]
Attack 3 (if still disarming, Bite): [roll3]
Attack 4 (Disarming or Attack, Talons): [roll4]
* If no longer disarming, and other three objectives have been met, then this is simply the attack roll, and Cookie takes [roll5]
TRIPS
Attack 3 (Bite, if tripping): [roll6]
Attack 4 (Talons, if tripping): [roll7]
Wow, this is the problem with pbp ... in trying to make sure of objectives-per-attack, this is probably the most complicated attack sequence I've had to map out .... and it isn't even that complicated. Whew.