They can land the Falcon 9 first stage in the middle of the drone ship. Any reason they can’t locate a perfect spot on the moon and land there exactly?
Earth orbiting GNSS provides excellent position information near the surface of the Earth but poorer position information near the surface of the Moon. That said, the Falcon 9 is equipped with a decent inertial navigation system.
Yep, not sure about the high altitude flight, but terminal guidance is certainly not GPS based. I think it's mostly radar & they even painted their landing zone with some special paint a while ago to get better radar returns.