Air Balloon is slightly better for Heatran than Shuca Berry since temporary immunity>one time weakening (Heatran will still take a lot of damage from a Ground attack even with Shuca Berry). Also, you can't really make a mix of an offensive Heatran and a defensive one; trying to do both makes it less effective at either role. So you'll wanna do it more like this:
-Heatran w/Air Balloon
Nature: Timid
Ability: Flash Fire
EVs: 252 Sp.Attack, 252 Speed, 4 HP
Moves: Fire Blast, Earth Power, Dragon Pulse/Hidden Power Ice, Flash Cannon
or
-Heatran w/Leftovers
Nature: Calm
Ability: Flash Fire
EVs: 248 HP, 8 Defense, 252 Sp.Defense
Moves: Lava Plume, Roar, Protect, Taunt/Toxic/Stealth Rock
Jellicent can use Scald over Surf, and can swap Will-o-Wisp with Toxic.
Thunder Wave and Gyro Ball don't mix well, since Gyro Ball is stronger when the opponent is faster than Ferrothorn; paralysis cuts Speed. So your options are to switch Gyro Ball with Power Whip, or Thunder Wave with Protect.
Landorus-T should use a Hasty or Naive nature. Brave reduces its Speed, which you don't want when you're using Rock Polish.
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