It's quite a shame because there aren't that many.
On the Congo specifically, there's
this timeline by Onkel Willie. IIRC correctly, Lumumba survives and the Cold War really heats up in the country. There's also
chapter XIII of my timeline (see the sig), which deals with political divergences in Congo and Angola in light of a Nixon victory in 1960. As long as you accept that conceit and read the footnotes, I suppose it could be read as a standalone piece.
I think Chad is only dealt with discursively, but there may some references to it in Drew's
Fear, Loathing and Gumbo timeline. I'm not sure if that's what you're looking for though, since that's the 1970s.
As for the C.A.R., I don't think that's been covered
at all.