We're never shown how Fredo got out of Havana. But, given the chaos caused by Batista's sudden abdication, it seems clear to me that he could only have gotten to NY 48 hours or less via some prearranged private means. Just as Michael had a plane waiting for him, Roth had a boat. And that's why I infer Fredo was on it.

Rocco's role in the Tahoe betrayal and shooting, if there was one, is truly a mystery to many of us here. Rocco was in charge of security for the compound--and the security failed. No one has ever explained how the Tahoe shooters died, leading some to conclude that Rocco killed them to keep them from talking. That would imply that he set up the Tahoe shooting. Of course, there's no proof of any of that.

Then Michael sent him on that one-way mission to kill Roth? Why? Because it was punishment for Rocco's role in the Tahoe shooting? And, Rocco accepted the mission. Why? Because he was trying to get back into Michael's good graces?

I'm not convinced that Rocco had any role in the Tahoe betrayal, but that doesn't mean I totally rule him out. One of those nice mysteries that FFC and Puzo left us with.