Sharpedo @ Life Orb
252 Atk 88 Def 84 SpD 88 Spe
Protect Crunch Waterfall Ice Fang
Because of speed boost, you don't really need to put so many EV's in Speed. The defensive EV's help him live a bit longer than normal, hopefully pulling off enough more protects to out speed other threats.
Virizion @ Life Orb
120 Atk 136 SpA 252 Spe
Work Up Giga Drain Close Combat HP Ice
Straightforward as you said, but a little take that I use. Ev's are more equally spread and Naive nature takes from Virizi's already stellar SpD stat, because it is frail on the physical def, and needs it as much as possible. After a work up, it's Atk hits 367 and SpA hits 375.
Heatran @ Leftovers
248 HP 100 SpD 160 Spe
Stealth Rock Lava Plume Toxic Protect
Switch in moves and item. Use protect to scout for a potential earthquake, and balloon is much too obvious. Very straightforward.
Landorus @ Choice Scarf
252 Atk 252 Spe 4 SpA
U-Turn Earthquake Stone Edge HP Ice
Nothing wrong. :P
Magnezone @ Leftovers
36 HP 252 SpA 220 Spe
Sunny Day/Magnet Rise Flash Cannon Thunderbolt HP Fire
HP Fire for steels. Your team is walled by steels rather well, barring Landorus. If you feel that Steels are giving you way too much trouble, run Sunny Day. Helps get that extra boost on HP Fire, and is helpful when encountering pokes such as Specially Defensive Skarmory. Other than that, Magnet Rise is always an option.
Slowbro @ Leftovers
248 HP 244 Def 16 SpA
Psyshock Scald Slack Off Toxic
Toxic is for other Slowbros, or other bulky threats that you want status'd. BTW, Slowbro is an evolution of Slowpoke, so it cannot utilize Eviolite. Other than that, just a little switch around of the EV's. Psyshock also combats Roserade's pitiful defense, which is a Pokemon that has the power to put a dent into Slowbro.