Correct, two pokemon, singles battle. One can be OU, the other can not be OU(NU,RU,UU,BL). Anyone can use SkarmBliss, FerroCent or T-Tar + Excadrill. This is to see who can come up with original strategies.
Your team follows you throughout the tourney. Anyone disclosing a persons team is dropped, so you won't have to worry about people knowing your strategy.