Well crying like a little bitch and confessing to the future Pope is a sign to me that he regretted it... remember he said "I killed my father's son" and the other stuff

and no I seriously doubt someone would reach out to Fredo.. again. A man like Roth wouldn't risk going through it all again, he could tell Michael was suspicious or atleast had his doubts near the end

and I forgot to say Mike had his little seizure moment in the kitchen with Vincent, he was shouting "Fredo"