I don't remember if I replied to your message or not, so I'm doing so now.
I do not recognize the name Mary Frances Longcore, but there is a connection in my husbands family between the stutson's and the longcor's. My husbands great grandmother was Emily Stutson, she was married to Timothy Longcor. They resided in Michigan. Timothy was from a family of 9 brothers who all resided in Ovid, MI.
I have a large Longcor/Longcore database. And there are several Whitaker's in it, but none named Mary Francis.