Always enjoyable to see these questions revisited, Pete. As for whether or not Roth engineered Pentangeli's survival:

Roth's plan was to lure Michael to Cuba, get the $2 million, and have him assassinated in the small hours of January 1, 1959. Why would he try to engineer an incredibly dangerous, split-second-timed rescue of Frankie? So that Frankie would hate Michael and testify against him at a Senate hearing weeks or months away, by which time, according to Roth's Havana timetable, Michael would be long dead?

And if Roth did intend for Frankie to survive, how would he engineer it? Call his man in the precinct and say, "Listen, Shultz, I want you to send a patrolman to Richie's Bar--but make sure he gets there at 3:43 and 22 seconds--not 3:43 and ll seconds, or 3:43 and 28 seconds--3:43 and 22 seconds!. Got it? Let's coordinate watches..."

Or, suppose Roth was lurking outside in a phone booth. He'd have to call the local police precinct and say, "Hello, 87th Precinct? There's a ruckus going on in Richie's Bar. You better send someone--but don't send him until 3:43 and 22 seconds..."

It was pretty obvious that the cop who happened on the scene wasn't clued in on it. And, as we saw, he got shot in the melee afterward.