Hmm, really interesting question... but to be honest it seems like a couple of these can do this rather easily so finding the "best" is kinda tough.
said, Zekrom can simply click on Bolt Strike for the win.
Mewtwo can use some stall-breaker set to destroy the combo.
Manaphy can use a simple Hydration/Rest/Tail Glow/Surf set to destroy both Blissey/Skarmory
Hell I can't see how anyone can lose, Excadrill (the one I think (at a glance) who is least likely to best the combo (because of Skarm)) can win this with some PP stalling shenanigans.