This is a really nice team (I'm talking about the theme and all, but the builds are awesome too :wink:)
There are two pokémon that come to my mind that are being used a lot that could be a possible threat: Cloyster and Ditto. I think you've read enough on Smogon and other sites to know about them, after all, been a week since last reply...anyway, I'm gonna talk about cloyster so this post will have some meaning.
So, people use the new move it has, Shell Smash, with it's "old" ability, Skill Link, to win games usually without even the need of the rest of the team (happened with me sometimes on PO, dunno if my building is faulty or it's really an insane attacking force). It gets +2 on both offensive stats and on speed, and loses 2 levels on the defenses. Then, it's Icicle Spear and Rock Blast to the end. The only pokémon I think that could survive is Empoleon, just to be aware of that, you may want to include some priority move on Empoleon or Dragonite, just to be a little safe.
I'm gonna have to go for a while now, sorry if I didn't help much.