Metagross
My prediction for Metagross movesets:
Fast moves:
Metal Claw (8 BP, 0.7 sec, 7 EPU)
Zen Headbutt (12 BP, 1.1 sec, 10 EPU)
Charge moves:
Meteor Mash (90 BP, 2.7 sec, 50 energy) New steel charge move
Psychic (100 BP, 2.3 sec, 100 energy)
Hammer Arm (130 BP, 3.0 sec, 100 energy) New fighting charge move
I chose these moves to give maximum trouble to all attackers except fire. Fire really needs a place in the meta, and Metagross is its biggest chance.
I would have chosen a fairy charge move if I could (to reduce the advantage Moltres has over Flareon) but Metagross can't learn any.
Answers
In the main series games, fairy Hidden Power is impossible. It was a move before the fairy type, and it is coded for backwards compatibility so that if you trade a pokemon forwards from an older game it keeps the same type.
Pokemon Go chooses Hidden Power type randomly, but has chosen to follow not allowing fairy.
We need actual fairy fast moves though. Even if they allowed for fairy Hidden Power, requiring random chance between all types to get the only possible fairy fast move would be beyond Niantic stupid.
