Flash does have his own city that he protects. It's called Star City. I've never known him to patrol Metropolis. I think Superman shouldn't be the sole survivor of Krypton. To me, it just seems a bit weird that out of billions of people on that planet only a baby made it out. The amount of survivors should be incredibly small, but I'd like for a few other Kryptonians as well.

I really like the idea of exploring Batman's detective side as that hasn't been shown once in a live action film yet.
For your Green Lantern and flash, which version of these characters are you going with?