@pokeysteve: I think everyone here could be a problem. Think there'll be a difference in the two rounds?
Nah. Hawkgirl just hits things. You can see her attacks coming for miles. Batman's team will counter. Shining Knight has a sword. Do you believe he can beat anyone on the other team? Warhawk doesn't have any feats that I can think of actually. Vigilante will be a factor in round two with his firearms. They can all probably dodge gunfire but not while fighting other people. He's a so-so fighter otherwise.
Vixen is the biggest threat being able to call on any abilities she needs be it speed or strength or durability. Hawkgirl and Warbird won't go down easy either but they don't bring much to their teams.
I'm having a hard time believing Aquaman is downplayed this much. Wonder Woman may be a bit stronger than him physically, and I can understand her beating him on land, but in water too? Are you serious? He can just summon gargantuan creatures to tire her out and then flick her for the victory. Even on land, take the episode from JLU where Grundy dies for instance: Aquaman has beaten Wonder Woman out of water.
Cartoons are not cannon. Pre 52 Wonder Woman is way more powerful than aquaman. Based on feats she will own him on land and beat him underwater. Sea creatures are not a problem for WW,she kills gods and fights Superman level characters. She could also fry them with Zeus lightnings inlcuding aquaman. If anything you are downplaying WW for thinking she is barely stronger than him on and thinking that sea creatures would put her down.