DUDE Your ECs are so freaking amazing. You seem SUPER qualified academically, like your subject tests, GPA, and SAT are top-tier :DD I’m not too familiar with certain ECs like Harvard Summer School or the trumpet masterclass, so I can’t comment on that. However, although I’m not an admissions officer, I think writing good essays are SO SO SO important–probably the most important. Since you’re a junior, you should draft your main essay over the summer! You should also consider sending an arts supplement!! I sent a visual arts portfolio to Stanford that increased the legitimacy of my awards and passion. If you claim to work with such an amazing trumpet player, you might be good enough to show admission officers. I know some schools also let you submit your research on Common App so you can submit your NHD project too. Overall, you are pretty qualified in my eyes no matter where you go, and I seriously mean that. 
Harvard Arts Supplement And/Or Research: Application Requirements
MIT Arts Supplement/Research:
I couldn’t find a CalTech’s website for Arts Supplements, but I think you can put your portfolio on a website and link your music in the additional information section on Common App if all else fails.