You are right about Batista, but wrong about Castro. He was not from an upper class family, he was from a rich family; there is a big difference, especially in Cuba. His viciousness was already well-known, his revilutionary gang had mounted an assault on an army barracks in 1953, assaulting the sick and wounded soldiers in the barracks’ hospital. Furthermore, the US ambassador to Cuba, Earl E.T. Smith, had already traveled to Washington to warn and advise Eisenhower that Castro was a red, and Eisenhower’s response was to remove Smith from his post and replace him with another ambassador. Castro’s favorable reception here was orchestrated by the NY Times and ultra left members of the State Dept who knew who and what Castro was. This is all in the public record, in multiple sources.
Did you ever see Andy Garcia’s movie, The Lost City? I think you’d like it. It has a great score (all Cuban music from that wonderful dance club era) and focuses on the members of a prosperous Cuban family at the time of the Castro takeover.