Would it help if I were completely honest with setbacks I've had throughout my high school career?

Answered

The simple answer I would say is yes, it's probably best if you're honest about setbacks in your application. What makes the answer a bit more complex is HOW you plan on describing those setbacks. I'll get to that point in a second but I wanted to touch on your concerns about class rigor. If you took all honors classes while in Puerto Rico then the admissions counselor who looks at your application will know that. That's going to come in handy when they look at your application and look at the academic rigor of your time in Florida. I don't think you're going to get impacted too bad by no honors or APs during your sophomore year. I'm not sure how it worked in your school but many times schools won't even offer AP classes to sophomores. Even if your school did I would bet that there were limited ones you could sign up for. In addition, you just moved from Puerto Rico and had to get used to a new language, a new place/school, and make new friends. That's A LOT for someone to handle at once. It's perfectly reasonable, at least in my opinion, and fairly easy to explain why you had slightly easier classes.

You're making up for your AP classes now which is great. I don't know how many APs you could possibly take at your schools but 7 APs seems to be a good number given your circumstances. You mention you're behind your peers in credits earned. Are you referring to credits from AP classes only or credits in general? I ask only because if it's the latter I'm curious if you are you on track to graduate on time? If you'll need an extra semester to graduate I'd try to get a few more APs/Honors classes in. But, if you're set to graduate on time, I wouldn't stress. As you mentioned, this is in the past and there is nothing you can do to change things now. It's not worth stressing over something you can no longer control and that mental energy is better spent elsewhere.

Let me get back to my point about how you present these setbacks in your application. The tone and way you describe these setbacks is going to be extremely important. Why? I'd argue there is a fine line between stating what happened and an admission officer thinking you are taking a "woe is me" attitude. If you do the latter it will not look good for you on your application. I'd be careful how you describe the fact you feel teachers were indifferent to your success while in PR and that you think your counselor in Florida judged your previous school. I'm not saying you can't talk about that but be very careful in how you do it and the words you choose. If you do include that information I would spend minimal time on it (like a sentence max) as you can use the already limited word counts in a better way.

For the last part of your question I'm confused if you're wondering what to include for extracurriculars or if you want to know if music is a good idea to write about for your essay. It sounds like you have the most experience with music so it might make sense to write about that, especially if you can incorporate your experience of moving from PR to FL and the impact that had on how you view music. I do think it's still worth talking about your love for writing and biology too if you can include it on your activities section of the app. Here are some Collegevine articles I think you might find helpful regarding ECs: https://blog.collegevine.com/how-to-improve-your-extracurriculars-junior-and-senior-year/ and https://blog.collegevine.com/your-complete-list-of-extracurricular-activities/ and https://blog.collegevine.com/extracurriculars-you-can-do-at-home/. The first article talks about how to improve your ECs in 12th grade, the second is a list of ECs you can consider, and the 3rd mentions ECs you can do at home.

Hope this helped answer your question! More than happy to answer any follow-up questions you have or clarify anything I said.