Purdue Engineering Waitlist - Chances?

I am an international student who applied to Purdue in January. I was disappointed to be wait-listed as going through the forums, a lot of people with similar/lower objectives got in. I realize the simple reason for this is my late application.
However, I would just like to know what is the procedure for admission from the wait-list. I wrote the SAT 2 subject tests and had the scores sent to Purdue.
Phy-800
Math2-750
Chem-720
I had previously only sent my earlier scores,
SAT1 - 1400
Math - 720
Reading and Writing - 680
and SAT 2
Phy-760

I have admits from CU Boulder (pretty pricey), UIC, and Illinois Tech. I’m also waiting for decisions from tOSU, UW-Madison (difficult), UMich-Ann Arbor (looks like a major reach).
I understand that Purdue takes in ~600 students from a waitlist of about 1800. It doesn’t look too bad, but what are my chances? Can additional credentials improve my chances?

I’m favoring Illinois Tech ($25k scholarship/ year) as it stands. Would like your thoughts on this too.