Only a UCLA student who has taken the classes for your minor would know if they were easier than other classes at UCLA and thus boost your GPA.
But yes, making good grades and enjoying the classes should be your two major concerns when choosing majors/minors/classes in general. There is no "penalty" for choosing a non-bio/chem major or minor. It can only help you because it makes you look more interesting, less like a robot, and gives interviewers something to ask you about and remember you by.
You could also benefit from your passion for music by volunteering at a place that gives lessons to underprivileged kids. I would be surprised if there weren't opportunities like this in LA. Extended participation in a program like that would make a big impact on an application.