>>49795718
Out of principle, I refuse to treat questions 1 and 3 as if they have answers.
On my interpretation of Hourai, and the album's name: because mount Penglai ("Hourai" in japanese) is considered a utopia, and because dolls are ersatz-human playthings, I like to imagine that it means something like "the human shapes being toyed with by paradise". Which is what happens in the story, I guess.