// Sorry it's out of order //
On Garchomp, not bad, but if it's going to have mixed moves, try:
Garchomp @Rocky Helmet
Trait: Rough Skin
Nature: Impish (+Def -Spe)
EVs: 252 HP / 120 Def / 90 SpD / 50 Spe
o EarthQuake
o Stealth Rock
o Draco Meteor
o Fire Blast/Dragon Claw
But you might want to consider keeping Garchomp fully physical, with moves like Swords Dance for sweeping and such, because it's honestly not much for Special Attack based moves.
On Bisharp, go ahead and use defiant if at all possible, because Inner Focus, on a steel type to protect from flinching isn't the most sensible thing to do when you could take advantage of that extra attack from Defiant, incase it's stats are lowered.
Okay, Ferrothorn. Yes, you have the general Ferrothorn idea, but, you should consider a Rocky Helmet on it if possible, because Leftovers, though useful, doesn't do much if your egging them on to hit you with Iron Barbs. Might aswell go the Garchomp route and get as much recoil damage on them as possible.
_
Okay, Talonflame, nice, but, if you're going to accept taking some damage from it's stronger recoil based moves, might aswell make it a full out shoot to kill Pokemon, right?
Here's my idea:
Talonflame @Life Orb
Trait: Gale Wings
Nature: Jolly (+Spe -SpA)
EVs: 252 Spe / 252 Atk / 8 HP
o Brave Bird
o Flare Blitz
o Roost/Overheat/U-Turn
o Swords Dance(or Roost/Overheat)
Unless that's not your style, your preference.
Rotom and Heracross look good, just if you want, go 4 HP EVs rather than SpD.
Best of luck to you on your battles,
-HF