Hey Scarlett! Where the heck you been? Welcome back!
I too had to go with Mama Corleone, simply because she stayed married to Vito thru thick/thin. I didn't know a couple of the names you mentioned, but with Appollonia dying and Kay divoricing Michael; Sandra lost Sonny, and we don't really know what their marriage was like, I think Mama deserves the title don't you??
TIS