What exactly are the EVs and items on these pokes anyway? It might be useful for us to know.
Anyway, while a special set on Greninja is viable, a mixed set is still arguably the most deadly version of Greninja:
-Greninja w/Life Orb
Nature: Hasty/Naive
Ability: Protean
EVs: 44 Attack, 212 Sp.Attack, 252 Speed
Moves: Gunk Shot, Low Kick, Ice Beam, Hydro Pump/Dark Pulse/Extrasensory/Grass Knot
On Metagross, Jolly usually>Adamant because base 110 Speed (in mega form) is a nice Speed to have. And you don't wanna run both Hammer Arm and Earthquake because you miss out on much needed coverage. Drop one for Ice Punch/Thunder Punch. If you don't feel like breeding for a Jolly one you can run an Agligross set instead. Same EV spread, just swap Hammer Arm with Agility.
Also, Lucario doesn't need 2 Steel attacks. Just Bullet Punch is enough. You'll want like Earthquake or Crunch for extra coverage.
I think another problem is that you have a lot of same types and some of the pokes don't exactly work well together. Almost all of your Pokemon are either Water, Dragon, or Steel type. Good types, yes, but you need more than those 3 types. Ludicolo really wants the rain, but you have no rain setter. Also you really need to get a Gale Wings Talonflame because that's the whole reason my it ever gets used in the first place, and you can do better than Carbink. Carbink is slow, is Taunt bait, has no offensive presence, and has no reliable recovery. If you go with a different Fairy type, you can at least complete a decent Dragon/Steel/Fairy core. Suppose some things to think about would be like....Clefable or Mega Dianice or Sylveon or something.
EVs for each Pokemon would be great. We don't need to know the exact stats.
Jolly is redundant with Agility/Rock Polish Metagross; Adamant is generally better, as the Speed loss can be made up for with Agility. While it seems weird, Grass Knot is a viable option to hit bulky Ground/Water Pokemon hard, plus it benefits from Tough Claws, despite being a special attack:
-Meteor Mash
-Zen Headbutt
-Hammer Arm/Earthquake
-Ice Punch/Bullet Punch/Grass Knot
Nature: Jolly/Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Metagrossite
Ability: Clear Body
or
-Agility
-Meteor Mash
-Zen Headbutt
-Earthquake/Hammer Arm
Nature: Adamant
EVs: 80 HP/252 Atk/176 Spe
Item: Metagrossite
Ability: Clear Body
Ludicolo functions best on rain teams. Outside of them, it fails so badly, as its Speed isn't that high.
Iron Tail Lucario is also a viable option, despite the move's inaccuracy, to hit Fairy Pokemon harder:
-Swords Dance
-Close Combat
-Extreme Speed
-Iron Tail/Crunch/Ice Punch
Nature: Adamant
EVs: 252 Atk/4 Def/252 Spe
Item: Life Orb
As Zekrom said, Gale Wings Talonflame is preferred over the Flame Body variants, as Gale Wings gives Brave Bird (or Acrobatics) priority to let Talonflame revenge kill just about anything that doesn't resist Flying, especially frail ones:
-Swords Dance
-Flare Blitz
-Brave Bird/Acrobatics
-Roost
Nature: Jolly
EVs: 88 HP/252 Atk/168 Spe
Item: Sharp Beak/Sky Plate/none
Ability: Gale Wings
or
-Bulk Up/Swords Dance
-Brave Bird
-Roost
-Will-o-Wisp/Taunt
Nature: Careful/Adamant
EVs: 248 HP/8 Def/252 SDef (Careful) or 248 HP/252 Atk/8 Spe (Adamant)
Item: Leftovers
Ability: Gale Wings
or
-Flare Blitz
-Brave Bird
-U-turn
-Steel Wing/Tailwind
Nature: Adamant/Jolly
EVs: 252 Atk/4 Def/252 Spe
Item: Choice Band
Ability: Gale Wings
Diancie (this is a superior Carbink in every single way possible):
-Diamond Storm
-Moonblast
-Earth Power/Hidden Power (Fire)
-Protect/Hidden Power (Fire)
Nature: Naive/Hasty
EVs: 16 Atk/240 SAtk/252 Spe
Item: Diancite
or
-Rock Polish
-Diamond Storm
-Moonblast
-Earth Power
Nature: Rash
EVs: 64 HP/16 Atk/252 SAtk/176 Spe
Item: Diancite
or
-Calm Mind
-Moonblast
-Earth Power
-Psyshock/Hidden Power (Fire)
Nature: Timid
EVs: 252 SAtk/4 SDef/252 Spe
Item: Diancite
Sylveon:
-Wish
-Protect
-Hyper Voice
-Heal Bell/Toxic
Nature: Bold
EVs: 252 HP/220 Def/36 SDef
Item: Leftovers
Ability: Pixilate
or
-Hyper Voice
-Psyshock
-Shadow Ball/Hidden Power (Fire/Ground)
-Baton Pass
Nature: Modest
EVs: 244 HP/252 SAtk/12 Spe
Item: Choice Specs
Ability: Pixilate
Clefable:
-Calm Mind
-Moonblast
-Soft-Boiled/Moonlight
-Flamethrower/Thunder Wave
Nature: Calm
EVs: 252 HP/172 Def/84 SDef
Item: Leftovers
Ability: Magic Guard
or
-Calm Mind
-Moonblast
-Moonlight/Wish
-Heal Bell/Protect
Nature: Bold
EVs: 248 HP/252 Def/8 SDef
Item: Leftovers
Ability: Unaware
or
-Stealth Rock
-Moonblast
-Fire Blast
-Soft-Boiled/Moonlight
Nature: Calm
EVs: 252 HP/184 Def/72 SDef
Item: Leftovers
Ability: Unaware
Outside of hitting Keldeo, Aerial Ace is useless on Scizor. Non-Mega Scizor should be using Choice Band if the Mega slot is taken up by Metagross:
-U-turn
-Bullet Punch
-Superpower
-Pursuit/Knock Off
Nature: Adamant
EVs: 248 HP/252 Atk/8 SDef
Item: Choice Band
Ability: Technician
Stick to Will-o-Wisp on Wash Rotom. You really don't need both Will-o-Wisp and Toxic on it at once; this deprives Rotom of semi-reliable recovery in Pain Split or Rest. Volt Switch > Thunderbolt; the former pairs well with Scizor's U-turn, as they can help your team build up momentum:
-Volt Switch
-Hydro Pump
-Will-o-Wisp
-Pain Split/Rest
Nature: Bold
EVs: 248 HP/216 Def/44 Spe
Item: Leftovers/Chesto Berry