Did they actually say that's who it was? If not, I would be curious to see what role Nightwing might play, though it seems like Roy Harper has already been established as the sidekick that had had enough and took off on his own. Not even sure who Kid Flash is. Since Flash was so chatty, I'm guessing he was Wally West, meaning Kid Flash is probably Bart Allen but. . .maybe not? I guess it really doesn't matter. They are taking so many liberties to begin with, that it might be best to just treat these characters as entirely new creations.