If I may share a thought on the Singing Mountian...
As I think someone above already noted, the area's theme on the soundtrack sounds very Zealian in origin. I've seen a screenshot or two that suggests the Singing Mountain was a lava-based area.
I wonder. Could the Singing Mountain be the site where humanity first laid hands on dreamstone?
A volcanic area would be churning rocks out from deep underground...
Not much to support the idea, really. Just conjecture. I like it, though.