Slight tip - never use those 1.1 booster items, they never provide enough of a boost when something like a Petaya berry does much better.
[email protected] Berry
EV: 252 Speed, 252 Sp Att, 6 Sp Def
Nature: + Speed, - Att
Thunderbolt
Thunder Wave/Wish
Substitute
HP Ice/Grass
I prefer HP Ice just for being able to hurt Dragons.
Charizard - only Aerial Ace gets a flinch chance from King's Rock, so I don't think it's worth using your item slot over. Lum Berry is my preferred choice of item.
[email protected]/Salac Berry
EV: 252 Speed, 252 Att, 6 Sp Def
Nature: + Att, - Sp Att/Def
Swords Dance
Aerial Ace
Rock Slide
Brick Break
Magneton - whoa, lot of mess to fix here:
[email protected]/Petaya Berry (Note: Magnet Pull)
EV: 252 Sp Att, 8 Speed, 125 Sp Def, 125 HP
Nature: + Sp Att, - Att
Metal Sound
Thunderbolt/Thunder
HP Fire/Water
Toxic/Rain Dance
Metal Sound makes Blissey run in fear, and Magneton's electric attacks can take down Skarmory (and he can't run due to Magnet Pull). Minor speed EV to be able to outrun most Skarmory too (but beware those HP Ground Skarm that sacrifice tanking to be able to KO Magneton).
Torkoal - not a fan of trying to boost both defences:
[email protected]
EV: 212 HP, 40 Att, 117 Sp Att, 141 Def
Nature: + Sp Def, - Speed
Amnesia
Rock Slide
Fire Blast
Toxic/Explosion
When they throw in someone to poison Torkoal - take em down with Explosion. That goes for all Blissey too. Torkoal's defences are high enough not to need Iron Defence, so go with Amnesia.
Dragonite - Safeguard-Outrage is an interesting tactic, but you lack versatility by going along this route:
[email protected] Berry
EV: 252 Speed, 252 Att, 6 Def
Nature: + Att, - Sp Att
Substitute
Focus Punch
Aerial Ace
Flamethrower
Time for more anti-Skarmbliss.
[email protected] Berry
EV: 252 Att, 252 Speed, 6 Def
Nature: + Att, - Sp Att
Dragon Dance
Rock Slide
Brick Break/Earthquake
Aerial Ace
Ye olde standard physical Salamence.