Kal'el is alive, and is on Earth currently, but the idea of Superman doesn't exist, I'll be playing him as his story instigates a part of the overall plot.

In regards to swaps of that kind, it really depends on the character. Batman's origin, as the successor of the a wealthy East coast family dating back a long way somewhat designates him as a white male, but, Dick Grayson could reasonably be of any ethnicity. Religious conversions are somewhat easier to change, as are places of birth and origin, for Gender swaps, run it by me first before developing the concept. Well, in reality, run any of these by me, but that especially might need some discussion.

Hope that clears everything up.