Regarding music, I would like to suggest a "See through mode or Music Mode" where you can see the backgrounds through blocks, where the blocks will have less opacity (transparent-ish) And then you'll be able to make song even with tons of obstacles, and/or be able to put backgrounds without hitting the notes that are covered by blocks.

This is a suggestion that supports the previous suggestion about adding the "Music Layer", if the devs are unable to add a music layer (which conflicts the background), then I think this will be a good temporary fix.

That's all~