To keep this thread going:

Remember that Pentangeli was supposed to be killed by the Rosatos in that bar, just as Michael was supposed to be killed in Havana. Cicci was totally loyal to Pentangeli, and would have been a threat to the Rosatos. I think if the Rosatos had succeeded in killing Pentangeli, they would have gone outside and killed Cicci, who was "waiting in the car." And, as it happened, Pentangeli survived and was taken into custody. So was Cicci. Sorrry, Willie, no New York "Olive Oil Business" for you.

I think there was no way Tom could have left the Family. He knew too much--business/political contacts, and incriminating info on Michael, Rocco and Neri. If Tom had told Michael, "Yeah, I'm taking that offer from the House and Hotels," Michael would have had him whacked as a defensive measure. If Michael had been killed, Rocco and Neri would need him to front the business. If he refused, bada-bing, for the same reason.

As for Tom and Fredo: Tom was loyal to the Family to a fault. He followed Michael's lead after Havana. We don't see any evidence of his trying to convince Michael to take Fredo back into the fold (as did Connie). But, he was Michael's liaison to Fredo-in-exile. Even if Michael had been killed, and Tom knew that Fredo had a hand in it, I think he would have found some rationale to support Fredo in some way, both to stay connected with the only family he ever had, and to avoid severing his ties, which would put him in mortal peril.