Referring also Michael and the $2 million

Michael was hot for Roth's Cuba deal until the Tahoe shooting

It seems Michael presumably knew Cuba was a lost cause as he turns up in Havana without the $2 million [The two million never got to the island]

I reckon Michael “happened to witnessing the suicide of a rebel being taken into custody and his rebels can win” was his get out of jail free card!

Then Michael has the $2 million brought into Cuba by Fredo after his rebels can win “solely as bait to keep stringing Roth along to the last minute so he could find out who the traitor was in his family” seems far fetched long shot!

Initially [until Roth's Moe Greene speech] Michael's reasoning was perhaps Michael believed he had Roth completely 'relaxed and confident'! in their friendship and until Roth gets the $2 million Michael was 'safe'! - Michael's own money for Michael's murder

It seems Michael didn't suspect Fredo until Fredo's slip up at the Superman club

So, how did Michael envisage he could find out who the traitor was in his family?
Was Michael hoping that Roth or Ola would be slippin'? again seems far fetched long shot!

Wonder the other business partners at Roth's birthday, were in, on Roth's guise “At the time of my retirement or death, I turn over all my interests in the Havana operation to Michael's control but all of you will share”
They all seem to accept Michael as Roth's heir-apparent somewhat meekly! too readily!