You appear to be well qualified to attend Brown or Stanford and do well. Unfortunately, the same thing could be said about perhaps 80% of applicants. Of course the acceptance rate is way lower at both of these schools.
This is the part of your question that concerns me. The highest ranked schools in the US are not all the same. You should be looking at the differences between them, and thinking about which of them are the best fit for you. Also, the top schools for any particular major are not necessarily the top ranked schools overall.
Also you need to pick out at least one and preferably two solid safeties.
Given that you apparently have some ability to speak French, and have great stats, one wild thought for a match (or maybe “near safety”) might be McGill (French is not needed to study there, but would make spending 4 years in Montreal more interesting). Admissions in Canada is very stats oriented, and your stats are strong. Also, McGill is quite strong for environmental sciences (which I think is also true of Toronto). Of course the winters would be quite different from what you are used to in California.
Given that you have been a varsity volleyball player for a full 4 years I do wonder whether you would be a recruitable athlete. That might improve your chances quite a bit.