
Bojas |
I've been using possession spells quite a bit since I started playing my current 11th-level wizard.
But lately, I've wanted to give the spell some more utility other than using possessed creatures as meat shields and I'd read in the spell description.
¨The body retains its Strength, Dexterity, Constitution, hit points, natural abilities, and automatic abilities. A body with extra limbs doesn’t allow you to make more attacks (or more advantageous two-weapon attacks) than normal. You can’t activate the body’s extraordinary or supernatural abilities, nor can you cast any of its spells or spell-like abilities.¨
So I get it right, no using barbarians' rage, using another wizard's spells, and so on.
But what about activating or using abilities that aren't Ex, Su, or Sp? like the rogue's sneak attack or trap-finding ability? it doesn't have a classification just like the weapon and armor proficiencies that you CAN use, so does the same apply? and EVEN if it where to be like that, what damage would you use?, the rogue's sneak attack dice or the first level damage?
What about combat feats then? are they natural because you don't need magic or anything supernatural for them to happen?
There doesn't seem to be an official answer or at least not one that I could find.
If it helps with anything I do have Intrusive Presence in case knowing about techniques is a requirement or something like that.

Zepheri |

you can not use activate ability but you still possess the pasive abilitys, example if you posses a figther the bravery, armor traning, weapon training,armor mastery and weapon mastery are all pasive so you can use if he have feat that are pasive like weapon focus or weapon fitness you can used but you can never activate a power attack or a vital strike
example 2 paladin: you gain aura of good, divine grace, aura of courage, divine health, aura of resolve, aura of faith, Aura of Righteousness and holy champion. the 1 that cant be used because require activation are: detect evil, Smite Evil, Lay On Hands, Channel Positive Energy, Divine Bond, Aura of Justice
in the case of a dragon you cant use his breath weapon. but in the case of a medusa her petrifying gaze is always active

willuwontu |
1)
The possessor uses her skill ranks, along with any feats the possessor has for which she still qualifies in the host’s body. The possessor doesn’t gain any of the host’s feats or skill ranks, but does apply bonuses and penalties associated with the host’s body. For example, when attempting Fly checks, a character who possessed a bird would use her own ranks in the Fly skill, but the bird’s Dexterity modifier and racial, size, and maneuverability bonuses.
You don't get the feats of the host body (nor skill ranks).
2) Class abilities are considered mental abilities, not physical abilities, thus you do not get any class abilities of the host when possessing them.

Azothath |
while the possessor "can’t activate the body’s extraordinary or supernatural abilities, nor can you cast any of its spells or spell-like abilities" they are still there and the GM can activate them as some are automatic. Toughness is an example. As you get HPs you effectively got Toughness. The possessor does not get them or have control, that's it really.
A case in point is Shambling Mound CR:6 Electric Fortitude(Ex). The mound is still immune to electricity but the CON bump is up to the GM as it's a reactive ability. It's best to zap it before taking control.
Advice: Beastspeak:D2 can prove very handy with animals.
Anecdote: In a high level game where only one adventurer was allowed, the party wizard magic jarred the rogue PC. They would then swap when the skills/spells of the other were needed via a tiny animal intermediary for the wizard. Thus 2 PCs in one body, a (talking) parrot, and two gems in earrings(foci), body in a Shrink Item doll.
You got the body, physical stats and HPs, and essentially avoid death - what more utility do you want?

Pizza Lord |
You keep your Intelligence, Wisdom, Charisma, level, class, base attack bonus, base save bonuses, alignment, and mental abilities. The body retains its Strength, Dexterity, Constitution, hit points, natural abilities, and automatic abilities. A body with extra limbs doesn’t allow you to make more attacks (or more advantageous two-weapon attacks) than normal. You can’t activate the body’s extraordinary or supernatural abilities, nor can you cast any of its spells or spell-like abilities.
Like Azothath said, while you are not supposed to get the feats of the body, there are some feats that clearly translate to the body itself that a GM can consider to be, if not actually 'acquired', then at least in effect.
Azothath mentioned Toughness as one such feat. That increases a body's hit points, since you get the inhabited body's hit points then the bonus from target's Toughness feat should still be there, even though you don't technically get the Toughness feat. The only time this really would matter was if you somehow possessed another feat or something that had synergy if you also possessed the Toughness feat; you wouldn't have it, you'd just be in a body with extra hit points from it.
The same could be said for feats like Great Fortitude or Lightning Reflexes. A GM could (I'm not saying I would or would agree with it) rule that those are inherent traits of the body and do apply to your saves in that body, but they could rule Iron Will as purely mental or inherent to the possessed target's soul or psyche or mentality.
The same could be said for the Improved Natural Armor feat, where the GM reasons that the creature's hide or scales are naturally and inherently tougher or the Improved Natural Attack feat where the reasoning might be bigger or sharper claws or teeth.