Mizpah,
If they didn't find three miracles attributed to Mother Theresa's intercession, then would not declare her a saint, but that doesn't mean that she is not in heaven. There is a difference. I had better let someone who cares answer that better. ;-)
Secondly, I'm unaware of any Roman Catholic "Saints" that have been less than saintly. I can think of a few "Catholics" that have been less than saintly, but I can't think of any canonised ones.