The "MVP" of my app idea would be a simple way to "stick" two or more songs together in a playlist. Basically if I find two songs that go great back to back, I would like to keep them together as I move them throughout my playlist.
Is this possible?
Well, you've got two toplevel options
Option 2 is generally better, as the user will be able to leave your app and still listen to songs.
In the case of option 2, you'd need to register for the Playlist's changed event, scan for the location of Song A, and move Song B after it. I don't think there is currently a way for it to be super efficient.