Nice growth you have going there! Yes I think some rocks will probably add some nice textures and contrast to the tank. As for the snails, if you don't want to put any puffers or loaches in, you can just put a piece of boiled vegetable in as bait and wait for the snails to all come munch on it before taking in all out with the snails. However, if the snail population isn't too out of control, I think you really don't have to do anything about it as they probably help clean up the algae around the tank real nicely.
Looking forward to see how the tank goes!