Salamence: Dragon Dance, Dragon Claw, Earthquake, Rock Slide
Greninja (Shiny): Surf, Ice Beam, Dark Pulse, Extrasensory
Klefki: Definitely keep!
Gardevoir: Keep.
Absol: Swords Dance, Sucker Punch, Psycho Cut, Play Rough (I would have Baton Pass over Psycho Cut, but I have NO idea how Baton Pass works for trainers other than the main character.)
Charizard (Mega X and Shiny): Dragon Dance, Flare Blitz (Or keep Heat Wave, whichever works for you), Dragon Claw, Earthquake
Honchkrow (Even though he's a pet, he should still at least have some moves): Sucker Punch, Brave Bird, Super Power, Haze (For clean getaways)
I still need movesets for two of your Pokemon plz