Cool character. As a rhythm game fan, I think the idea for the ultimate is too gimmicky. I've rarely seen rhythm games mixed into other game types work well. Late Night Live would distract you by making you basically switch from Deadlock to O2Mania just to do damage. Seven can do that with only one button press. The idea of Naima's skills being expressed as music is still really cool, though.
Maybe the ultimate could go for a jazz improvisation theme. You get a buff that gives you medium AOE damage over time, but over the duration, you can press different buttons to grow different stats, like AOE, damage, or slow. You get to "play" the ultimate like an instrument, matching it to the situation.
Still though, music character. I love that kind of theme. Nice work.