I haven't played Crisis Core yet, so I can't comment on Banora...

But Healin is presumably quite close to Midgar of Kalm, likie Bolivar has said. It's outside the wasteland around Midgar, apparently in the hills. There are plenty of rocky spots on the FFVII worldmap where it could be.

In fact, I once had a dream where I was playing a remake of FFVII. Full-3D, it was fantastic. It was the original FFVII, but you could visit Healin too. It looked great. About halfway between Kalm, Midgar and the Chocobo Ranch.

WRO Headquarters seem to be in roughly the same general area as Midgar. Again, outside the dead wastes, but close enough to be a short journey from one to the other.