There are 2 ways you can go with your team. Either rebuild it completely or go the Baton Pass way. I'm going to try to cover both as best as I can here.
Ninjask
Keep Baton Pass: The moveset could use some adjustments. The moveset below allows Ninjask to beat opposing Ninjask instead of being setup bait if carrying Silver Wind.
Rebuild: A Spikes setter like Skarmory, Cloyster, or Forretress would be a good lead.
Ninjask @ Leftovers / Salac Berry / Liechi Berry
Ability: Speed Boost
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Hidden Power [Flying]
- Swords Dance
- Baton Pass
- Substitute
Skarmory @ Leftovers
Ability: Keen Eye
EVs: 252 HP / 248 SpD / 8 Spe
Careful Nature
- Spikes
- Whirlwind / Roar
- Taunt
- Drill Peck / Toxic
Forretress @ Leftovers
Ability: Sturdy
EVs: 252 HP / 4 Def / 252 SpD
Careful Nature
- Spikes
- Rapid Spin
- Toxic / Hidden Power Ghost
- Earthquake
Cloyster @ Leftovers
Ability: Shell Armor
EVs: 252 HP / 8 SpA / 64 SpD / 184 Spe
Timid Nature
- Surf
- Spikes
- Rapid Spin
- Ice Beam
Lunatone
Keep Baton Pass: Natural Cure, great bulk, and a bigger movepool make Celebi the best passer of Calm Minds in ADV OU. You're much better off using it over Lunatone.
Rebuild: Celebi is are much better as an offensive Calm Mind user (and a better Pokemon in general) for the reasons mentioned above.
Celebi @ Leftovers
Ability: Natural Cure
EVs: 252 HP / 164 Def / 60 SpD / 32 Spe
Bold Nature
- Psychic
- Giga Drain / Hidden Power [Grass]
- Recover
- Leech Seed
Celebi @ Leftovers
Ability: Natural Cure
EVs: 252 HP / 76 SpA / 180 Spe
Timid Nature
- Giga Drain
- Hidden Power [Fire]
- Calm Mind
- Baton Pass
Vaporeon
Keep Baton Pass: Looks good to me
Rebuild: Suicune's stats and access to Calm Mind make it a better choice.
Suicune @ Leftovers
Ability: Pressure
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
- Surf
- Rest
- Sleep Talk
- Calm Mind
Suicune @ Leftovers
Ability: Pressure
EVs: 252 HP / 192 SpA / 64 Spe
Modest Nature
- Surf
- Ice Beam
- Calm Mind
- Substitute
Charizard
Keep Baton Pass: It can work I guess, but there are better Baton Pass recipients out there.
Rebuild: If you're not going to be using Baton Pass, Salamence or Zapdos are much better Flying types.
Zapdos @ Leftovers
Ability: Pressure
EVs: 4 HP / 252 SpA / 252 Spe
Timid / Modest Nature
- Thunderbolt
- Hidden Power [Grass]
- Roar
- Toxic / Thunder Wave
Salamence @ Choice Band
Ability: Intimidate
EVs: 4 HP / 252 Atk / 252 Spe
- Hidden Power [Flying]
- Rock Slide
- Earthquake
- Brick Break
Salamence @ Leftovers
Ability: Intimidate
EVs: 24 Atk / 232 SpA / 252 Spe
Rash / Naive Nature
- Dragon Claw
- Flamethrower / Fire Blast
- Hidden Power [Grass]
- Rock Slide
Metagross
It isn't a Special/Mixed Metagross, and it isn't a tanky one either. Since you have 4 Physical moves and want to do as much damage as possible, Choice Band is your best bet. Brick Break should be replaced for Hidden Power [Bug] or Rock Slide. Don't use Armaldo.
Marowak
Keep Baton Pass: You're better off going with a Pokemon that is immune to phazing, like Suction Cups Cradily and Octillery and Soundproof Exploud, to ensure phazers cannot break the Baton Pass chain.
Rebuild: You can either use Tyranitar since it does a lot of immediate damage with its powerful attacks, and passive damage with its automatic, permanent Sandstorm as well as Spikes support. You can also use Blissey if you're going to use Skarmory, since Skarm+Bliss is an incredible defensive core.
Cradily @ Leftovers
Ability: Suction Cups
EVs: 252 HP / 92 Atk / 164 SpA
Quiet / Modest Nature
- Giga Drain
- Hidden Power [Fire]
- Rock Slide
- Recover
Exploud @ Leftovers
Ability: Soundproof
EVs: 220 HP / 180 Atk / 108 Spe
Adamant Nature
- Return
- Shadow Ball
- Fire Blast
- Earthquake
Octillery @ Leftovers
Ability: Suction Cups
EVs: 252 SpA / 4 SpD / 252 Spe
Timid / Modest Nature
- Surf / Hydro Pump
- Ice Beam
- Fire Blast
- Hidden Power [Electric] / Hidden Power [Grass]
Tyranitar has too many sets for me to cover. Some of the best sets can be found here.
Blissey @ Leftovers
Ability: Natural Cure
EVs: 212 HP / 252 Def / 44 SpA
Bold Nature
- Soft-Boiled
- Ice Beam
- Seismic Toss / Flamethrower
- Toxic / Wish / Thunder Wave