Hi jersey!!
Well, I understand that Mount Sinai will start sending letter between late may/early june. I attended their revisit weekend on late march (I'm wait-listed,though). However, that was for the minority students that were either "accepted or are highly attractive in the wait list" (according to one of the deans). Although, I'm wondering because many of the students invited were not minority.
As for Cornell (also wait-list) the assistant dean let my pre-med advisor know that my likelyhood of getting in is small b/c I'm actually waiting for the spots of other minority students that may drop. I guess that for the overall non-minority wait-listed pool there is a much better chance of being accepted...hopefully this information helps.