Bonnie & Caroline - Katherine & Elena were put together as a guess, kinda. I figured Kat & Elena could pull off the 'who am I', which might help them. And it seems like Bonnie is closer to Caroline than she is Elena anymore.

Katherine could pretend to be Elena, which would help her with the Salvatores, Caroline and Bonnie, and then secretly go after them. Elena would be the deadweight of the team, but I still think they'd win.

well we don't know how strong the werewolves are yet and michael trevino said that they have one major advantage over vampires.
so for now Katherine I think can beat everyone else

Yep, and Katherine is so strong she could probably beat everyone, even carrying Elena on her back, but the Salvatore brothers are strong, and (even though they don't admit it) they have a strong bond, and when they have to they can work together, and cooperate well.