Just to address the legacy thing briefly:
These days, most legacy admits to these colleges, like you, are very well-qualified academically. Princeton actually provides some useful evidence on this issue in the form of their incoming Frosh Surveys published by the Daily Princetonian. Specifically, if you look at the Academics section, Testing subsection, you can do some legacy/non-legacy comparisons:
Legacies skew more consistently high scoring than non-legacies. Indeed, these colleges sometimes argue their data shows legacy admits who have such high academic qualifications are particularly good bets to do well in their courses, which is part of why they like to admit them.
To the extent legacy helps, then, it is observably more in the sense that these colleges get a lot more applicants who are highly-qualified academically than they can admit. Non-academic factors are then what cuts that bigger pool down to a much smaller admit pool, and legacy is a non-academic factor that can help you survive that cut.
But not because as a high numbers legacy you are a worse bet to do well academically. If anything, more the opposite.
So personally, I don’t think a high numbers legacy admit to these colleges needs to worry about being competitive academically. If you are lacking anything, it might be some sort of non-academic activity or essay or so on that really stood out, which is how high numbers non-legacies would likely have managed to survive that same cut instead.
But even if so, lacking a non-academic distinguishing factor is not going to be a negative indicator for academic performance.
Edit: Oh, and in case this wasn’t clear, I also vote for you being done and just enjoying the rest of your senior year. It is an enviable position to be in, you should feel great about it, and you should squeeze all the benefit out of it that you can.