Casting in my not-body?

[avr]

There's polymorph spells. If you can get one of them off somehow or another then the body you're possessing can be changed into something better for casting spells from. Anthropomorphic animal has a useful duration for this.

With followers collaborative thaumaturgy can let you cast silent or still spells without level increase or the actual feats. Arcane concordance and/or blessing of fervor could work this way too.

Deaf curse oracles get silent spell for free on all their spells.

Beastspeak is a spell for talking and using verbal component spells while an animal. Note that some spells just don't have somatic components. A few don't have verbal components, but I can't think of any which lack both.

Some non-psychic spellcasters can get a few psychic spells. Sorcerers/bloodragers/blood arcanists with an esoteric dragon bloodline & wizards with the psychic preparation arcane discovery that I know of.

A couple of levels of warpriest lets you cast self-only spells without somatic components a few times a day.

[Jeven]

Pathdo wrote:

What are the easiest ways for a non-psychic to be able to cast all their spells after using greater possession to control enemies not suited to casting spells. (Like a rabbit, for example.)

Before casting the spell you could toss a spare component pouch on the ground and then after you possess the poor bunny rabbit it can use it's little buck teeth to rummage around in the pouch lying on the ground and pull out components.

Like the dog and the stick, animals don't have hands, but they can still grab stuff!