Another question...
Are we assuming that Roth gave the go-ahead for Frank to be murdered or that the Rosato's took it upon themselves?
I believe Roth gave them the go-ahead. Roth probably told them he'd use his relationship with Michael to resolve the issue. So, they waited on his go-ahead. No doubt they heard about the Tahoe shooting. So, Roth must have told them: "Pentangeli tried to kill Michael. He failed. He gave me the go-ahead for you to whack him. Michael even conned him into meeting with you..."
BTW: What was in it for Roth? Had the Tahoe shooting succeeded, Frankie would have been on the run. The Rosatos would take over the olive oil business as Roth's allies, maybe even give him a cut of their take.
Also, Roth didn't really need/want the 2 million from Mike did he?
No, he didn't--and very insightful of you to spot that, Immobiliare.
Michael had been encroaching on Roth's gaming empire since returning from Sicily, even whacking Roth's best friend, Moe Green. Roth’s goal was to eliminate Michael. His strategy was to play on Michael’s obsession with becoming legitimate by pretending that Michael was his heir-apparent. Roth doled out bits and pieces of his empire to Michael, all the while buying time for an opportunity to have him killed. Roth’s strategy was succeeding.
The Havana deal would make Michael king of legalized gambling in the Western Hemisphere. Roth had tantalized Michael with the promise of his crown jewel prior to the Tahoe shooting. I’m guessing that Roth also told Michael, before the shooting, that he’d have to make a big payoff to Batista, the Cuban dictator. He may have mentioned $2 million, or he may not have put a price on it.
At that point, getting the money wasn’t Roth’s primary goal. His goal was to buy time for an opportunity to whack Michael. The money for bribing Batista was a means for Roth to add credibility to his Havana-deal fiction: Michael would expect that a big bribe would be needed for him to get Batista’s permission.
Anthony’s party provided Roth with his golden opportunity to have Michael whacked, and to have the finger pointing at Pentangeli. Roth would have to forego the $2 million—but,so what? $2 million was a small price to forego to simultaneously get rid of Michael and Frankie, and put his own guys in charge of New York. Only after that plot failed did the $2 million become important to Roth. I'm guessing Roth needed the $2 million to pay off Batista to have his thugs kill Michael. Nice touch: Michael pays for his own assassination.