What are my chances of getting into Columbia, Cornell, Johns Hopkins, of Tufts?

I think you have a very good chance at all of those schools if you can raise your SAT score, or if you simply don't send it since it's so much lower than your ACT. Also, you don't have any leadership positions...that could pose a problem. Is there anything unique about you that would make you stand out? Have you proven that you're very pionate about any of your extracurriculars? Bronx Sci is really competitive, and colleges know that, so your GPA is very impressive. Columbia may be a bit of a reach, but the other three are good matches. Good luck!