We're never told in the movie that the other guys with Roth at his birthday party were investors, although it's not unreasonable to expect that.
The movie strongly implies that the "Lakeville Road Group" were one of his other investors.
"Lakeville Road Boys" = Mayfield Road Gang (Moe Dalitz and Sam Tucker).
Eddie Levine of Newport" = Eddie Levinson of Lexington, KY.
Again: The script never says they were "investors," but it is logical to assume they were.
For all his smart, Lansky screwed up big-time in Havana. US Congress ruled that American investors could own casino interests either in Nevada or Havana, but not both. Lansky and Santos Trafficante chose Havana. Lansky put up $5 million of his own and investors' money, plus $6 million from Batista, to build the Havana Riviera. When it opened in March 1958, it was Havana's biggest and plushest casino/hotel. Ten months later it belonged to Castro.
Sonny, have you ever been to Cuba?
