they are almost always going to favour people from their own league.
im basing this off people who are coming from YC and telling me how it is.
some folks applied to YC in the past, get rejected and then find some Harvard graduate running with their ideas they submitted.
2 people submit the same idea. 1 gets in, the other doesn't. yc, basing their decision on the founder themselves and not so much the idea, chose person 1, who had more of the founder characteristics (determination, ... i forget the rest).
maybe there's a higher chance that between 2 people, 1 from harvard 1 not, the harvard person has those characteristics. could be they "learnt" it there, or they had to use those same skills to even get into harvard, or whatever. but it doesn't mean they got in because of the harvard degree
apply that same logic of thousands of people, maybe it looks like they prefer harvard candidates.
to YC you are just another lotto ticket out of the thousands of founders, be very wary about divulging information such as finances or what works.
its akin to going to a hedge fund, letting them in on an edge you discovered, and expecting them to not trade on that information without you.