Regarding the advice to speak to alumni, does anybody have suggestions for best alumni to talk to for not-for-profit applications?

P.S. Thanks for the informative and thoughtful post.

EDIT: at the risk of creating more competition for my eventual application, here's a relevant quote in an interview of Watsi's co-founder:

I asked him if he would recommend that other non-profits apply to YC, and without missing a beat he replied, “yes. For three months we were able to focus on our mission and our products alone. We didn’t have to worry about fundraising or entering competitions or getting grants. We focused on our product and solving a problem. We grew like crazy in the last three months. We went from getting $2,000 of donations a week to $12,000. That’s a crazy growth….Every non-profit should have this opportunity for focus.”

http://thenextweb.com/insider/2013/04/06/catching-up-with-wa...