When Mike gives Fredo *the kiss* was that a signal to his bodyguard to take Fredo out? (I believe he still thinks his bodyguard is alive). But then again I don’t think Mike wants Fredo dead at that point.

Or was it his way of letting Fredo know that he knows and he just wants to frighten him.

Or was it just an outpouring of emotion. The way he grabs his head afterward is quite emotional.

Or was it just some classic Catholic imagery.

Or all of the above.

?

His bodyguard was already gone at that point

I think it's the outpouring of emotion.

Is the "Kiss of Death" a real thing? Did Michael tip his hand that Fredo was a goner?

Michael nodded to the bodyguard as soon as Fredo made his fatal gaffe at the Superman show. The bodyguard went off to kill Roth.

Pete, I think the kiss was the famous "kiss of death" associated with the Mafia. Michael tipped his hand, though--I can see why Fredo wasn't convinced when Michael shouted at him, "You're still my brother," and didn't get into Michael's car.

TB, that's how I see it.

Also, in a deleted scene, right before the New Year's Eve party, Michael was listening to Bobby Rydell's Kissing Time.