I love these kind of games and I'm kind of disappointed I did so bad at this. The physics seemed a bit off to me, but maybe it was just me.
I decided on Espeon, simply because I can deal with it being male.
I didn't actually try for Espeon per se; I decided I'd catch both Vaporeon and Espeon orbs, and take whichever one I got more of. Kind of disappointing that Glaceon and Leafeon orbs don't appear until level 4; if you could get female versions of these I'd get Glaceon out of principle. The very idea of a male Glaceon is simply appalling, so Espeon it is.