I'm kicking this off with Grapple, Aid Another and Attacks of Opporunity (AoO).
Currently in Fallen Empires we have a situation were Vren (unarmed) wants to help Torrak grapple an animated witch's cauldron.
Vren lacks Imp Unarmed Attack, she also lacks Imp Grapple.
Torrak has Imp Unarmed Attack, and he also has Imp Grapple.
Vren is acting first, and wants to Aid Another to give Torrak a +2 on his Grapple vs the Cauldron.
Multiple Creatures: Multiple creatures can attempt to grapple one target. The creature that first initiates the grapple is the only one that makes a check, with a +2 bonus for each creature that assists in the grapple (using the Aid Another action). Multiple creatures can also assist another creature in breaking free from a grapple, with each creature that assists (using the Aid Another action) granting a +2 bonus on the grappled creature's combat maneuver check.
As a standard action, you can attempt to grapple a foe, hindering his combat options. If you do not have Improved Grapple, grab, or a similar ability, attempting to grapple a foe provokes an attack of opportunity from the target of your maneuver.
The way I'm reading this is, Vren is making an Unarmed Attack to Aid Another vs AC10. That provokes an AoO. If she had Imp Unarmed then no AoO, even if she had Imp Grapple I might see it as legit to have no AoO. But as it stands I'm thinking Vren draws an AoO from the Cauldron because this is an attack and she's unarmed.Aid Another
In melee combat, you can help a friend attack or defend by distracting or interfering with an opponent. If you're in position to make a melee attack on an opponent that is engaging a friend in melee combat, you can attempt to aid your friend as a standard action. You make an attack roll against AC 10. If you succeed, your friend gains either a +2 bonus on his next attack roll against that opponent or a +2 bonus to AC against that opponent's next attack (your choice), as long as that attack comes before the beginning of your next turn. Multiple characters can aid the same friend, and similar bonuses stack.
You can also use this standard action to help a friend in other ways, such as when he is affected by a spell, or to assist another character's skill check.