To swallow a spell with Regurgitator, it seems like you have to ready an action for it (unless the spell is ongoing). Is this the intention?
Also, someone just put the Spellthief out of a job, I like Regurgitator better.

It also seems you have an error in Swallow whole rank 3, it should probably say 1 medium, 2 small, 4 tiny etc.

I grin at the thought of combining this with Reaping Mauler. Sleeper lock+Swallow whole anyone?