There were quite a lot of communist governments in Africa actually. Angola and Mozambique both had civil wars in which a Western- (and SA-backed) rebel army attempted to overthrow their respective Communist Soviet-backed governments. Other communist countries included Benin (overthrown by a popular uprising), Congo-Brazzaville, Somalia and Ethiopia, the latter of which was a particularly repressive Communist regime led by the military leader Mengistu Haile Mariam, who committed genocide against his own people and was at least partly responsible for the Ethiopian famine of 1984 (ie the one that Band Aid made famous).

As for left-wing African leaders who weren't officially 'Communist', a good example is Julius Nyerere, the first president of Tanzania. He was a proponent of 'African Socialism' and the concept of Ujamaa, a form of communal socialist empowerment. One of his main goals was the creation of farming communes under the Ujamaa model, and under Operation Vijiji, Nyerere attempted to forcibly relocate the whole of Tanzania's rural population to these communes, with very limited success.

Yes. After independence from Portugal, the socialist parties in Mozambique and Angola set up one-party socialist states based on the Marxist-Leninist model. This led to civil war between the Soviet-backed ruling parties (FRELIMO and MPLA) and American-backed anti-Communist rebel groups (RENAMO and UNITA).

The ruling parties in both countries have since renounced hard-line Marxist-Leninism. Both countries are also nominally democratic, but the socialist parties still hold most of the political power. You can still see traces of the countries' socialist pasts by looking at the emblems on their flags, which are clearly inspired by the Soviet hammer and sickle.