I started to write this as a Harry Potter crossover - the baby is Neville from the HP books - but never got very far with it and can't now find the file. I think I posted a fragment of it here a couple of years ago.
That sounds like an interesting twist, Marcus. I sure hope you find it. You've piqued my curiosity on why Neville was left with Lois and Clark or if he were actually from Krypton, too.