Hi Gabriel, Your ECs are impressive but it’s your grades, class rank, and standardized test scores that will be considered first.
What is your GPA on a 10 point scale? Do you have a general idea of your rank in percentile terms?
Have you taken the TOEFL or equivalent? Are you planning to take the SAT or ACT? While elite schools are still test optional for this year, they might not be for next year. A strong SAT or ACT will also add context to your grades.
To answer your question, the overall chance of getting into any of these schools is less than 10% and closer to 5%. I know many students with perfect grades and test scores and varied ECs that got rejected from these schools. For international students your chances are much smaller than that.
Your chances at Duke improve if you are academically qualified and if you apply binding early decision but they will still be quite small.
As others have mentioned, if attending school in the US is the dream, apply to schools that meet full financial need and are need-blind for admissions. Some colleges are need-blind for domestic (US) students but not for international applicants. So read the fine print.
The challenge is that the private colleges and universities that offer full need based aid and are need blind are also the hardest to get into. So you should balance your list with schools that are more realistic and also affordable. There are also some schools, generally public state universities, that give automatic scholarships for certain grades/test scores. If those are of interest, let us know and I’m sure you will get many suggestions.
Also keep in mind transportations costs, health insurance costs (can be around $3,000 annually), and other incidentals for your budget.
Finally, as I’m sure you know, the federal university system in Brasil is excellent so you should have many fine choices there if you don’t get into an affordable college or university in the US.
Best of luck!