I agree that taking two AP math classes at once is not needed. Only do this if you are very strong at math and want to do it.
You are also signing up for a large number of AP classes. Are you sure that you want to take on this tough of a course load? Yes once you get to university all of your classes will be university level, but there won’t be seven of them at the same time.
This is not a race to see which students can take the most AP classes at once.
My recommendation is that you take what is right for you, and do not try to guess what admissions at Stanford or any other highly ranked university wants you to take.
And of course Stanford is not in the Ivy League. When I was there it was in the Pac 8, which later became the Pac 10 and then Pac 12. Now it is in the Atlantic Coast Conference, which to be honest makes no sense to me at all, but regardless it is not an Ivy League school.
I was a math major. One daughter was a biology major. These majors do not overlap much. A biology major will take quite a few classes that overlap with premed classes, which are typically quite tough. There will also be a number of lab classes, which can take quite a bit of time. Math students really should take some CS classes, which again can take quite a bit of time (it is amazing how long a simple bug can take to reveal itself). If you end up dropping back to one major that it entirely reasonable, but of course this is something that you can figure out after you have been in university for a while.
And I agree with @tamagotchi that you do not want to take high school graduation requirements over the summer. Completing your graduation requirements is the top priority. There will be time to take probability and statistics and/or physics with calculus and/or anatomy when you are in university (although taking some physics in high school is a very good idea).
Then it might be reasonable, as long as you want to work that hard. Of course if you do get to Stanford or UC Berkeley, they will also require a large amount of hard work.
I think that highly ranked universities expect applicants to have taken a rigorous schedule and done well in the classes. However, you do not need to pile up the tough classes to a crazy level. Take what is right for you subject to also completing high school graduation requirements and you should be fine.
And keep an open mind regarding which schools to apply to. You really do not need to attend Stanford or Berkeley or UCLA as an undergraduate student to do very well in life, nor to have a good career, nor to get to attend a university at this same level for graduate work if you get to that point.