Wow, sounds great. Does the Singing Mountain have lava in it? There was a CT:DS environment with flowing lava, but I can't think of any in CT:SNES that had flowing lava. If not, we can just use the glowing floor effect seen in the Ocean Palace and the Sun Keep.
If you're seriously considering the Fire Dragon God, what we'll have to do is make most of the body part of the background, with the head and maybe the hands Size 1+ enemy sprites.