Choice Scizor is better with U-turn so that it can scout the opponent. Its EV spread should also be 248 HP/252 Atk/8 Spe to let it take less damage from hazards when it switches in as maxing out HP leaves its HP divisible by 8, which means that it gets KOed if it switches in to Stealth Rock 8 times (assuming it never got hit during those switch-ins).
Blissey's EV spread should be Calm with 4 HP/252 Def/252 SDef to let it take physical hits better.
Fire Punch is important on DD Dragonite, as this lets it hit Steels Pokémon outside of Heatran (who's immune to Fire thanks to its Flash Fire ability). You should give up ExtremeSpeed or Roost for it.
Flare Blitz >>>>>>>>>>>>>>>>> Fire Punch on Infernape, even if you have Iron Fist as your ability, as an Iron Fist-boosted Fire Punch is still weaker than Flare Blitz. Also, Close Combat doesn't benefit from Iron Fist, despite the animation. Iron Fist is still useful for powering up ThunderPunch, though.
Fit in Rapid Spin on Starmie somewhere (like, say, over Psyshock), as Dragonite really hates having Stealth Rock on the field.