I don't think Hillary or Castro are Communists. Clinton seems to favor a lot of socialist ideas (I would have to disagree about socialism being "the ultimate form of democracy"), but I honestly don't think she's a communist.

Castro, while he was/is allied with communists, doesn't seem to me to be too concerned with any political-economic movements. He's a dictator and he's in charge. He doesn't seem to follow any school of though, at least not strictly. And I know he strongly distrusted the Soviets after the Cuban Missle Crisis in which his Khruschev used Castro and his country in a game of chicken against the U.S.