No, they definitely won't let you refer someone to take your place. That would be incredibly unfair to the rest of the wait list. Class size was 60 last year so should be roughly the same this year.
I think the wait list isn't ranked because once they have an idea of who is joining they'll try to re-balance based on diversity of candidates. I'm sure there's some clustering of candidates that can help them send the second / nth wave of acceptances.