I'm nowhere near done, but it looks like it'll take a while yet to fill in all the roles (and then after that you need actual challengers, hah). For E4 I was thinking maybe the 12 leaders can just battle each other first, but then that'd be pretty screwy if you got matched against whatever you're weak against. Can't think of any other way, though.
Was hoping that the pokemon bank would open soon, that would save me a lot of effort, heh.