which mega?

Clefable @ Leftovers
Ability: Magic Guard
EVs: 252 HP / 172 Def / 84 SpD
Calm Nature
- Moonblast
- Thunder Wave
- Calm Mind
- Soft-Boiled

Keldeo-Resolute @ Choice Specs
Ability: Justified
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Hydro Pump
- Scald
- Secret Sword
- Icy Wind

Heatran @ Leftovers
Ability: Flash Fire
EVs: 252 HP / 4 SpA / 252 SpD
Calm Nature
- Lava Plume
- Toxic
- Taunt
- Stealth Rock

Latios @ Life Orb
Ability: Levitate
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Draco Meteor
- Psyshock
- Defog
- Recover

Ferrothorn @ Leftovers
Ability: Iron Barbs
EVs: 252 HP / 88 Def / 168 SpD
Relaxed Nature
IVs: 0 Spe
- Gyro Ball
- Power Whip
- Leech Seed
- Spikes
WHICH MEGA WOULD BE BETTER FOR THE TEAM
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Diancie-Mega @ Diancite
Ability: Magic Bounce
EVs: 4 Atk / 252 SpA / 252 Spe
Hasty Nature
- Moonblast
- Diamond Storm
- Earth Power
- Protect
          OR
Lopunny-Mega @ Lopunnite
Ability: Scrappy
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- High Jump Kick
- Return
- Fake Out
- Quick Attack