Re: empoleon and mesprit
Mesprit is much better as a Calm Minder. Choice Specs is something Azelf or even Alakazam does better.
180 Spd, 252 Sp. Attack, 78 HP
Last slot is for coverage. Grass Knot after a few boosts will put a lot of pain on Tyranitar, and Psychic can put a dent in Heracross switch-ins.
EDIT: I just saw it's Quiet. That's alright, too.