Creating Player as Familiar/Patron

[TobyFox2002]

I am running in a game where things are a bit topsy-turvy. And I was wondering if Anyone out there might have some advice.

I am trying to create a class (or an archetype) that the FAMILIAR (or in this case) PATRON is the player and the Witch well... essentially the companion. I'm trying to do it in such a way that its relatively balanced (although, this is for a silly game so.. its bound to be a bit powerful.)

The issue I'm running into is, well, I'm not sure how to redo the companion chooser so it selects the playable races rather than animal/companion races. I was wondering if there was any way to do that without a massive overhaul or a mechanic based rework.

I think if I get that part down, I can fiddle with the rest.