What about party members? When people join the party, are they taught Marxism-Leninism?
Wikipedia says 5.3 million people are party members, which is about 5.3% of the population, so if that's true you'd think it would spread the ideology a bit.
Another question: when you say liberalism what do you mean? Is there political correctness and that weird American identity-politics stuff in Vietnam?
China: very very high, maybe 90%, their material conditions have progressed in leaps and bounds. Most people want a better life for their kids: the government is delivering that = most people are satisfied with the government's performance
Cuba: much more mixed, people are suffering economically. Says you, "Oh but that's the fault of outside influences"... well your particular explanation of the causes will chime with a certain percentage of the population only, there's lots of angry anti-government people in Cuba, but they may not be a majority, hard to put a number on it
Vietnam: I have no info on this
Check out Fearless Blood - it's exactly about Chinese bandits in that era