Ubers! It's always nice to see a new user who knows what they're doing.
First off, not much synergy at all. The sets are all messed up and your team doesn't work well together. I mean, why use Tentacruel in Ubers without rain? Granted, Kyogre does pop up about half of the time, but, still! Also, three Psychic types, messed up EVs. Let me help you.
Deoxys
- Grass Knot, to hit Kyogre and Groudon
- ExtremeSpeed, to take out Deoxys-Speed's Sash
- Timid Nature, so he can outspeed Scarfogre and other Scarfers
- Superpower, so he can OHKO Darkrai and Tyranitar
New Moveset:
Deoxys @ Life Orb
Trait: Pressure
Timid Nature
EVs: 4 HP, 252 SAtk, 252 Spd
Moves:
- Psycho Boost
- ExtremeSpeed
- Grass Knot
- Superpower
Mewtwo
- Too complicated EVs, make it a simple sweeper with 252 SAtk/252 Spd/4 HP
- It needs more coverage moves to hit more Pokemon
New Moveset:
Mewtwo @ Life Orb/Expert Belt
Trait: Pressure
Timid Nature
EVs: 252 SAtk, 252 Spd, 4 HP
Moves:
- Psystrike
- Aura Sphere
- Shadow Ball
- Thunder/Flamethrower/Ice Beam
Mew
- Will not be able to sweep very well
- Cannot take more than a hit or two with the current EVs
- Needs to be replaced for some sort of staller or wall.
New Moveset:
Ferrothorn @ Rocky Helmet
Trait: Iron Barbs
Impish Nature
EVs: 252 HP, 252 Def, 4 SDef
IVs: 0 Spd
Moves:
- Gyro Ball
- Leech Seed
- Protect
- Stealth Rock
Hydreigon
- Too many special sweepers
- Cannot outspeed most of the metagame
- Probably should go physical
New Moveset:
Hydreigon @ Choice Scarf
Trait: Levitate
Adamant Nature
EVs: 252 Atk, 252 Spd, 4 HP
Moves:
- Outrage
- Stone Edge
- Dragon Claw
- Earthquake
Arceus
- Needs more simple bulk, 252 HP/252 Atk/4 Spd will work well.
- Needs a means of recovery: Recover
- Needs a status block, Lum Berry over Silk Scarf
New Moveset:
Arceus @ Lum Berry
Trait: Multitype
Adamant Nature
EVs: 252 HP, 252 Atk, 4 Spd
Moves:
- Swords Dance
- ExtremeSpeed
- Shadow Claw
- Recover
Tentacruel
- Doesn't provide much support without rain
- Is out of synergy with the rest of the team
- Needs to be replaced with more support...
New Moveset:
Chansey @ Evolite
Trait: Natural Cure
Calm Nature
EVs: 252 Def, 252 SDef, 4 HP
Moves:
- Heal Bell
- Thunder Wave
- Wish
- Seismic Toss
Hope I helped!