French high school student

Did you mention what major(s) you might be interested in or did I miss it?
UIUC admits by major and the difficulty of admissions at CMU may differ a lot by college.

Also, all rankings have to be considered in context and what schools are better for what may differ by goals as well as fit.

For instance, if you have Wall Street/the City as a goal, this is approximately how people there would rank: http://finance.yahoo.com/news/hiring-managers-25-best-schools-161911937.html

For a software developer:

https://■■■■■■■■■■■■■■■■/edu/rankings/us/undergraduate-software-engineering
https://■■■■■■■■■■■■■■■■/edu/rankings/us/undergraduate-software-engineering-small

For preparation for a PhD, I may have different lists and include LACs, depending on the subject.

Large merit scholarships may be a possibility as well, but not at many of the topmost schools on your list.

The feel of different schools would be pretty different as well.

Do you plan to go back to France after graduation or elsewhere in Europe?

Any reason not to consider UK unis or McGill in Canada?

I’m not sure why SAT1 even exists, since if you’re applying to a college that require subject tests, you’ve got presumably a set of subjects in which you’re excellent and nothing forces you to pick math. Math1 has a wicked curve and is almost ignored because it’s basically the same as Reasoning test/math.
Anyway, yes, focus on math2. Beware that some of the topics are only covered in TS.