Current student here.
Your numbers and credentials look solid. You certainly have a great shot. That being said, the process is sometimes kind of random, and it may come down to your research interests and whether there is a current professor who really wants to have you in his/her lab.
That being said, good luck!
Not that guy who posted in the results. (Wow 5 pubs???)
Anyways, I also got into Columbia with the Dean's Fellowship. 170/165 (Q/V), 850 Chem, 3.6ish GPA (not extraordinary, I know), 3 summers and 1 school year of research, double major. I've taken quite intensive courseloads, with a ton of music (piano, voice) on top. No publications. Interest in Atmospheric Chem. Think I got good LORs.
Hope that helps.