RPG Corner: Ye Olde League of Justice

Your buddy who usually runs your gaming group calls you to pitch a new idea for the group:

The Justice League as played in D&D (any version)!

How would you assemble the team? How would you build them, in terms of class, alignment, race, etc., using only the rules for the edition you choose? Which JL members would complete your roster for your adventuring party of, say, 4-6 players? Would you start everyone at Level 1, or would you prefer to get as close as possible to the regular incarnations of the characters and start them out at various levels? What kind of equipment would you use to help replicate their powers?

And most importantly of all, would Robin be a Henchman?

I'd love to hear what you'd do with that scenario, other than hanging up on your buddy the DM!