Any characters can pretty much go anywhere in this game and pretty much any combination is guaranteed to have 100+ damage TA combos because they all have their fillers and wall carries.
From the sound of things, Wang+Leo is the way to go. I've always wanted to learn Leo, but I seem to have this ridiculous 5-character limit in every fighting game I play. And I've already invested a lot of time into the Laws, Jin, Miguel, Eddy, Raven, and miraculously Heihachi. I'd try out Leo if it weren't for the risk I'd end up forgetting how I play my other mains x_x