Evolve low CP exclusive moves for PvP
We know that for the minor leagues there will be a CP cap of 1500 and 2500. Use this CD to evolve exclusive moves under those caps to use in PvP.
Answers
I think mm metagross is really the only one you'll need, possiblt double rock tyranitar, Dragonite (but likely TM to outrage).
Most of the others dont really have the kind of bulk needed to do (what we expect) Pvp to be like, but venasaur and Charizard do however have the little niche of countering top tier pokemon we likely will see (metagross for Charizard and kyogre, possible groudon, tyranitar, and defensively countering raikou, and even though I dont think he'll be a top contender in PvP, machamp.)
Exactly. The lower leagues will most likely involve some pokemon that are totally outclassed by the current leaders in the dps charts, due to their average stats.
Definitely most community day exclusives will be good, but not all of them. Tyranitar is a good rock attacker due to high CP, not due to it's moves.