No doubt Michael was slippin' blinded by Greed and taken in by Roth's promise as his successor even after Pentangeli's warning

I agree the late night phone call doesn't sound like Roth / Ola instructed the Rosatos to kill Pentangeli and as posted I too reckon Roth didn't order Pentangeli's murder

If the Roatos acted on their own to whack the caporegime of the top Mafia Don which wouldn't sit kindly with any Don
also it looks bad for Roth that his partner tried to kill Michael's partner when he went to make the deal, at his request

I can't see Roth telling them that he was going to whack Michael in Havana and Michael still had his own men and there was plenty he could do to avenge the murder

The questions still lingering
1. Why would Clemenza make such a promise? What did Clemenza owe the Rosatos?
2. How can he promise these territories that are not his?
3. Why even slippin' Michael didn't seem fazed