Your academic qualifications (GPA and test scores) look pretty good. When you say your school “doesn’t do weighted”, do you mean your school doesn’t offer AP classes or do you mean that you would have to self-calculate your W GPA? I would be a bit concerned if it is the former, since AP classes are important for admission into these schools. Additionally, I would suggest you take some SAT II subject tests in Math 2, Biology, and Chemistry to show colleges your interest in these areas. Try to score above 750 (that shouldn’t be a problem for you).
Your ECs look really good, and the only thing that may look a bit off is your focus in the humanities area since you have done a lot of literary ECs (literary magazine editor, poetry, short stories, etc.) I am not sure these particular ECs are super relevant to your intended major, but I do think they make for an excellent topic for college essays + supplements where you can talk about your interest in these areas as well. I think you still have a lot of ECs that show your interest in biology/chemistry so I would not worry about having to be more involved in STEM activities. Your profile looks really good and I think you have a great shot at most of these schools! Good luck! I would really appreciate if you could chance me back here: http://talk.collegeconfidential.com/what-my-chances/1995754-chance-me-low-gpa-rank-cornell-rice-wash-u-ucla-etc-p1.html