I think Zweilous is going to be pretty damn good in this metagame. The only Steel-type is Klang which is 2HKO'd by Superpower. The only 2 Fairy-types are Carbink, which is 2HKO'd by Aqua Tail, and Wigglytuff, which is also 2HKO'd by Aqua Tail.
Bad calcs, these things can all take 2 hits from CS...