Chiming in with my opinion, but given Batman is only like his second year I have huge problems with Harley being about; even more than I do with Poison Ivy. This is a "One Universe" game not an "Ultimate" game, so shouldn't most characters go by the "don't reinvent the character and ultimize them; only minor changes, not major ones." rule?

[quote]do I need to clear it with him to play that character?[/quote]

It's kind of what the games ask with legacy characters: to make sure you can work something out with the parent character's player so to not step on too many toes.