Oh,
Serebii has the Ability/Item/Move info on the Mythical Pokemon being given:
NOTE: All of them are at Level 100.
Mew: Ability: Synchronize. No item. Move: Pound.
Celebi: Ability: Natural Cure. No item. Moves: Confusion, Recover, Heal Bell, & Safeguard.
Jirachi: Ability: Serene Grace. No item. Moves: Wish, Confusion, & Rest.
Darkrai: Ability: Bad Dreams. Item: Enigma Berry. Moves: Dark Void, Ominous Wind, Nightmare, & Feint Attack.
Manaphy: Ability: Hydration. Item: King's Rock. Moves: Tail Glow, Bubble, & Water Sport.
Shaymin: Ability: Natural Cure. Item: Micle Berry. Moves: Seed Flare, Aromatherapy, Substitute, & Energy Ball.
Arceus: Ability: Multitype. No item. Moves: Judgement, Recover, Hyper Beam, & Perish Song.
Victini: Ability: Victory Star. No item. Moves: Incinerate, Quick Attack, Endure, & Confusion.
Keldeo: Ability: Justified. Item: PP Max. Moves: Aqua Jet, Leer, Double Kick, & Bubble Beam.
Genesect: Ability: Download. No item. Moves: Techno Blast, Magnet Bomb, Solar Beam, & Signal Beam.
Meloetta: Ability: Serene Grace. Item: PP Max. Moves: Quick Attack, Confusion, Round.
... Okay, can I meet whoever made these decisions and SLAP THE STUPID OUT of them?! I could criticize them in detail, but I can sum it all up in two:
1. Why are only some of them holding items? Like if you can't think of a good item to give them how about just one of the rare berries? Actually scratch that, give them all rare berries. Like they have the Micle and Enigma Berry, how about the Rowap, Jaboca, and Custap (heck, you could even have some holding a Starf and Lansat since they're hard to get).
2. Okay, you don't want to give them any special moves, that's fine. But still what in the world are with those movesets? Some don't have a full 4, others are moves they first learn, except others have moves from all over their movepool, Victini doesn't have V-Create,
and Shaymin has Aromatherapy which it doesn't learn!