I was thumbing through my trees and shrubs of MN book from the UofM. I combed through about a third of that book, and that's what jumped off the page at me. Fine serrated leaf edges, and the blossom arrangement fits chokecherry.
***side note. That wild card cherry we found at my brother's place last year seems like a pin cherry. The hitch was finding a cherry that grew in clusters and could persist into fall.