Vaporeon @ Leftovers
Ability: Water Absorb
EVs: 212 HP / 252 Def / 46 SDef
Calm Nature (Special Defense +, Attack -)
Hydro Pump
Ice Beam
Wish
Rain Dance
Persian @ Life Orb
Ability: Technician
EVs: 6 HP / 252 Speed / 252 SAtk
Timid Nature (Speed +, Special Attack -)
Swift
Water Pulse
Hypnosis
Nasty Plot
Qwilfish @ Leftovers
Ability: Swift Swim
EVs: 168 HP / 252 Atk / 88 Speed
Adamant Nature (Attack +, Special Attack -)
Waterfall
Poison Jab
Explosion
Swords Dance
*-May replace with Feraligatr. I would also like to be able to outrun the standard ScarfGarchomp and explode in it's face if needed.
Magnezone @ Leftovers
Ability: Magnet Pull
EVs: 172 HP / 84 Speed / 252 SAtk
Modest Nature (Special Attack +, Attack -)
Thunderbolt
Hidden Power [Ice]
Magnet Rise
Substitute
Mesprit @ Leftovers
Ability: Levitate
EVs: 252 HP / 176 Def / 80 SAtk
Bold Nature (Defense +, Attack -)
Psychic
Thunderbolt
Ice Beam
Rain Dance
Kingdra @ Mystic Water
Ability: Swift Swim
EVs: 252 Atk / 88 Speed / 168 SAtk
Naughty Nature (Attack +, Special Defense -)
Waterfall
Draco Meteor
Surf
Ice Beam
In my opinion, Vaporeon is not a good lead, as 8 pokemon out of the top 10 leads (Gengar, Gyarados, Bronzong, Tyranitar, Yanmega, Ninjask, Azelf, Infernape) don't care about it and can set up on it.
The next thing I see is lack of a status absorber. You would have to force a sweeper to be incapacitated if Gengar, Bronzong and stuff start spamming Sleep moves.
I don't see the role of Qwilfish on this team. Most people already know what Qwilfish does - Explode. Therefore the strategy is predictable and Qwilfish would be a burden on your team.
Kingdra wants the Atk and SpA Evs switched, 168 Atk already guarantees the 2HKO on Blissey.
Your team is weak to Scarf sweepers like ScarfCross, as they can decimate your team and your only "counter" to them is Mespirit and Vaporeon, and Kingdra can only come in and revenge when the Rain is up.
Lead LO Gengars also rape this team, 2HKOing Vaporeon, OHKOing Magnezone (70% chance), Mespirit (100% chance), the only thing that can safely switch in is Kingdra, and it will get Hypnotised by Gengar without Rain.
So, fast sweepers are the downfall of this team, if the opponent gets a good matchup at the start, Rain Dance won't even be up. SDLuke and DDGyara among other fast set-up sweepers will also pose a significant threat to this team.