Wishing Star
Astral Charm Owner
Lava Surf is something I've wanted to see in the main games since they introduced it in Pokemon Ranger: Shadows of Almia.
It would probably be strictly for traversal purposes, rather than for exploration purposes. You can explore a water route and see trainers and dive and such, but you can't really do that with lava. All you'd be able to really do with it is go from one edge of a lava pool to another.