Ok so one of my friends is looking at another forum and sees a high level game, 17th level. He wants to come up with a cool concept like a body thief.
So He was thinking of running a Beast-Bonded Witch and having his character Twin Soul jump into a body, and then cast Major Mind Swap (Learned from Samsaran Mystic Life) to perma-steal a body and not just that but also to get their abilities.
His logic is this. Yes when you jump into a body via Magic Jar you do not gain the special abilities of the body. Well the Soul is gone because of how the Twin-Soul worked. But now using Major Mind Swap you can permanently swap your mind into this body. So you are no longer using the effects of Magic Jar but Major Mind Swap.
I think his idea is to use his Familiar to Twin-Soul into the target body to kill it and take it over. Then Major Mind Swap You into the Target body. The Familiars soul goes into your previous body, and can shift into its own at will once you heal it. But now your mind is in this new body. And Mind Swap and Major Mind Swap doesn't seem to ban you from using special abilities of the new body.
So problem with this plan is that Mind Swap and Major Mind Swap function like the Possession spell which says "You can't activate the body's extraordinary or supernatural abilities, nor can you cast any of its spells or spell-like abilities."
Also Major Mind Swap only functions on a creature of your same race as a further limitation.
In addition to the above, there's this.
Mystic Past Life (Su) You can add spells from another spellcasting class to the spell list of your current spellcasting class. You add a number of spells equal to 1 + your spellcasting class's key ability score bonus (Wisdom for clerics, and so on). The spells must be the same type (arcane or divine) as the spellcasting class you're adding them to.
A witch is arcane, she can't add psychic spells to her list via this ability. Wizard and bard, yes.