First off, the room you are designing sounds so neat! I bet your birds will love it... I know mine would!

Your birds should be fine with some soft music at night. Infact, they might really enjoy it. Lilly, one of my cockatiels, suffers from night frights. Through some trials, I found that it really helps prevent these frights when I play music softly when the main lights go off and her night-light comes on. None of the other birds have "complained" and their behaviors haven't changed. They still get plenty of sleep.

If anything, you can try it for a night and see how they do. I can always tell if my fids didn't get a good nights sleep when they are irritable in the next day. :]