Hey! This is a great stall-esque team!
I can't suggest much to deal with the threats you mentioned since SS Scrafty and CB Flygon will almost always be a problem to stall in UU, though I feel CM Slowbro could fit in somewhere :P What I do think you should consider is, putting Toxic or Rest over Foresight on Blastoise, and trading Fire Blast on Camerupt for Flamethrower / Lava Plume to get a secondary answer to SubRoost Zapdos in case Snorlax, for whatever reason, is in no condition to fight. I also don't know what the 156 EV in Defense achieve, but I guess they're there for a reason, otherwise you could opt for max/max Sassy on it.
Kudos on the awesome team and use of underrated Pokemon in Rotom-F (outside of Hail at least) and Camerupt!!!
EDIT: Oh, Luvdisc'd :D