I'd drop Flare Blitz for Swords Dance, just for that extra damage. You could also run banded, but if you don't like that idea, its fine as it is.
No changes need to be made; Ice Shard threatens it, but that's not the most fixable thing in the world. EDIT: The scarf is boosting your speed already, so you should run adamant.
Nothing to be changed here.
Better Mega Kangaskhan counter:
Gengar @ Gengarite
Ability: Shadow Tag
EVs: 124 HP / 252 SpA / 132 Spe
This shuts down Mega Kangaskhan like nothing I have seen before. First, because of Shadow Tag, they're locked in with this monster. Secondly, if they already set up Power-Up Punch, Clear Smog ruins their day. Thirdly, if they're running Shadow Claw or Sucker punch, Disable completely denies their attempts at hitting you. And if they're running Earthquake, you can stay as normal Gengar, which has the Levitate ability. Most Mega Kangaskhans run Fake Out, Power-Up Punch, Return, Shadow Claw / Earthquake / Sucker Punch. It's almost garunteed.
Nothing needs to be changed here either.
You should have more EVs in Special Defense. That's all I really have to say.
Good team overall, but severely lacking a special wall. I think Mega Venusaur can serve as one with its Thick Fat ability, but you could just replace a pokemon if you want. I hope this satisfied you, and good luck!