Unfortunately, despite your 700 in math, I fear you mayl not get in. I say this because you have a number of deficiencies:
Your class rank is rather low. Not even close to the top 10%.
Your CR SAT score is rather low.
Your unweighted gpa is rather low.
Your ACT is also slightly low.
I would say that FSU is a more realistic bet.
I would take the SAT again, and try and raise the CR to a 600.
Miami is moving up in the rankings lately. It is becoming more difficult to get into.
If I were the admissions offices, I personally would want to see how you did on your AP tests. If you passed them, then this would show that your gpa is probably low because you go to a good high school with no grade inflation.
College admissions is not done merely on merit anymore.
There are affirmative action considerations, geographic considerations, and the like.
I do not agree with this, but that is the way it is.
In my opinion, essays are just an excuse to apply subjective criteria. Why should an essay count for more than 4 years of work. Obviously, it shouldn't. The college doesn't even really know whether a good essay was written by the applicant.
The fact your kid, with his fine record, was rejected shows that the process has in many ways become a farce.
I suspect many were accepted that have a record nowhere near as good as your son's.
You have no choice but to move on.
Last year, my son had a 2300 SAT, and 14 AP courses, yet was rejected at many schools, who admitted kids with far less impressive records.
I had my son, who did not have much in the way of ECs, apply to schools in England, where they go basically by hard data. I figured he should play in a game where the rules favored him.