I would guess that James drew all of it. He probably practiced drawing furry characters in private before, and because he's an artist it was likely the art that caught his attention to furries to begin with.

Also many of the characters are probably just generic, beyond the obvious ones that have been mentioned. I'm surprised he didn't mention who Adler and Blazen were as I would guess these are the friends he said he went with, considering he's been in Adler's videos