The Congo mission was a disaster, although a well-intentioned one. There's a pretty good account of it in Jon Lee Anderson's biography "Che: A Revolutionary Life". While Fidel was publicly following the post-Missile Crisis Soviet line about "getting along" with the West, behind the scenes he was backing Che's guerilla war plans in Argentina, Congo, and finally Bolivia, all of which were based on their experience in the Sierra Maestra (i.e. starting wars in the countryside, where the government is weak). This was closer to Mao's guerilla theories than Kruschev's more large-scale tactics. Anyway, the peasants in the Congo weren't trying to rise up with him, the rebels all disagreed with each other, and they barely got out alive.
I don't know what happened in Angola or Tanzania. I know that Algeria was a frequent stopping-place for Cuban agents abroad, and Ben Bella was friends with Fidel and Che until he got overthrown.