Please rate my team & give some tips!

My team:

1. Darkrai (Sassy)
Stats: 296 HP, 196 Atk, 222 Def, 303 Sp. Atk, 255 Sp. Def, 279 Speed.
Item: Leftovers.
Moveset: Dark Pulse, Focus Blast, Dream Eater, Dark Void.

2. Raikou (Hasty)
Stats: 361 HP, 220 Atk, 160 Def, 248 Sp. Atk, 237 Sp. Def, 292 Speed.
Item: Leftovers.
Moveset: Extrasensory, Spark, Thunder, Discharge.

3. Ho-oh (Quiet)
Stats: 358 HP, 323 Atk, 203 Def, 281 Sp. Atk, 354 Sp. Def, 189 Speed.
Item: Leftovers.
Moveset: Flamethrower, Sacred Fire, Psychic, Earthquake.

4. Lugia (Lax)
Stats: 381 HP, 198 Atk, 335 Def, 204 Sp. Atk, 292 Sp. Def, 289 Speed.
Item: Leftovers.
Moveset: Blizzard, Fly, Surf, Thunder.

5. Mewtwo (Modest)
Stats: 354 HP, 230 Atk, 216 Def, 447 Sp. Atk, 216 Sp. Def, 359 Speed.
Item: Leftovers (might swap for "Odd Essence" please tell me if i should!)
Moveset: Psychic, Icebeam, Psycho Cut, Recover.

6. Celebi (Modest)
Stats: 402 HP, 208 Atk, 233 Def, 327 Sp. Atk, 232 Sp. Def, 233 Speed.
Item: Big Root.
Moveset: Leaf Storm, Recover, Giga Drain, Psychic.