Has a monkey!
They can't. As Rabbit said.I wasn't aware Daemon Prince's could take familiars in the new codex. Unfortunately my friends borrowed my codex for the week, so I can't check.
Tzeentchian Sorcerors (but not Aspiring Sorcerors from TS units) can take more than one power, as it states in their entry that 'models with the Mark of Tzeentch may take one additional power.'I only meant to point out that the Tzeentch daemon prince is the only one capable of taking two psychic powers (unless of course you are right about princes taking familiars).
This one's actually in the Chaos Codex itself. 'A psyker may only attempt to use on psychic power per turn,' on page 88. Exception made for models with the MoT, with standard firing restrictions.I should have remembered that. Though after checking the BGB entry for psychic powers (pg.52) I don't actually see anything limiting you to using only one psychic power per turn. (though that is how my friends and I have always played it, especially with the existence of wargear like Ahrimans black staff) Is there another entry on psychic powers? Or am I missing something?