Decided to give this a go. To start, your team looks decent. I like it. But, it has a few flaws.
Politoed
Choice Specs and Hypnosis? No. Lefties and HIdden Power Electric. Scald is an excellent choice here.
Not needed, but you can switch Spd EVs into SDef for reliable set up.
Abomasnow
Switch the nature to Relaxed, and Id suggest A fully defensive EV spread.
Move set looks good.
Tyranitar
Time to get Physical. Give it a Sash and Adamant nature. EVs 252 Atk / 4 Def / 252 Spd
Switch Ice Fang to DDance. With all this weather, the Opponent should be switching like crazy. Switch Aqua Tail to Pursuit. A DD boost with it can easily make it into a Revenge Killer.
Ninetales
Not bad. No suggestions.
Volcarona
Switching. Mew can fit this team exceptionally well.
Mew @ Choice Specs
Trait: Synchronize
EVs: 252 SAtk / 252 SDef / 4 Spd
Modest Nature (+SAtk, -Atk)
-Aura Sphere
-Thunder
-Solarbeam
-Blizzard
Gets all the weather boosts, and Aura Sphere has the accuracy / coverage.
Raikou
Is getting switched to Espeon.
Espeon @ Light Clay
Trait: Magic Bounce
EVs: 4 HP / 252 Def / 252 SDef
Calm Nature (+Def, -Atk)
-Light Screen
-Reflect
-Toxic
-Protect
Provides team support, stalls, and has a great Ability. Nuffsaid.
Sorry if this wasnt the help you were looking for, but I tried my best and did it all from a phone :D
