I know some of us are running on the assumption that all (or very near all) stages are going to return alongside all veterans, and unfortunately one of my favs Brinstar Depths has not been seen yet. But like, I feel it's almost confirmed with that gorgeous new rendition posted on the Smash website, since Brinstar Depths only exists in Smash, it's not even an actual location name in the Metroid series. If they wanted the song, I doubt they would have named it after a Smash stage instead of just Kraid or Kraid's Hideout.
Basically, I just love the Melee Metroid stages and can't wait to play this version over as many things as the game will let me.