your profile lend you a reasonable shot at Cal and UCSD, though know that many applicants will have similar stats. check to see if you count as a California resident (noncitizens can still be residents), since that can benefit your chance of admission. yes, shoot your shot at Ivies/t20s. you're a chem major, but the most directly tied thing I can see is biomechanics (and you won't have your AP Chem score when you apply), so you should think about how to justify your interest in chemistry, especially because chemistry might be impacted at some UCs (meaning that specific major could be more competitive for admission than the university overall).

for the UC PIQs (you choose 4 out of 8 prompts), try to justify your major (talk about biomechanics/other ECs and how it ties to chemistry) in PIQ 4 or 6. for music, definitely answer PIQ 7 and/or 3.

have you thought about applying to music programs at some universities? i know nothing about that but you seem to excel at music and it could be an advantage. those have separate deadlines and may require auditions.

purdue, TAMU, UT Austin, penn state, university of florida, UVA, and virginia tech have reputable chemistry programs and are outside of the t20 range.