Don't worry about Lucario, TTar revenges it with ease, and if it has bullet punch then Rotom can take it out.
Anyway I think thunder punch should replace ice punch on metagross. It lets you hit bulky waters way harder and also prevents skarmory from setting up on you. Also consider using life orb because you have no way to boost your power. To help with your mixape weakness you could try scarfing rotom and changing it to a rotom-W. A simple moveset of T-bolt, shadow ball, Hydro Pump and Trick should help with infernape and even stall teams (kind of)