I think that you have a good GPA, and your course load is mostly competitive, but your extracurriculars seem to lack a focus/passion, and there is no strong leadership in any of the extracurriculars. (To be honest, colleges might think you did some of your extracurriculars just to put them on your resume) I think certainly if you believe that you are quite talented at the piano then by all means submit a supplement, but I hope you realize that admission will never count first on your music audition. In fact, that will probably be the last thing they look at if they look at it at all. Academics, test scores, extracurriculars, and essays are by far more important. As for your individual schools, I would say NYU is a low reach and Vanderbilt is a reach/high reach. I don’t know much about Oberlin College, sorry.
I would love it if you could chance me back! http://talk.collegeconfidential.com/what-my-chances/1796275-what-do-you-think-of-my-chances-are-at-these-universities.html#latest Good luck!