I love the idea of letting bards play their own music, but it's probably more complicated that it sounds- The music emanates from a block location giving it the problems associated with making a player give off light, and it may be even tougher since moving the source seems like it would reset the music. If a moving music source can be added, I think Bards should require the disc to play the music.
The second... Sort of redundant but the Happy Days reference alone would justify it. Heyyyy!
Jukeboxes shouldn't do as much as note blocks in my opinion. Jukeboxes require a diamond, whereas note blocks just need a bit of redstone. The recipe for note blocks should have included string, but that's neither here nor there.