Африканчик https://www.google.com/search?client=safari&rls=en&q=африканчик&ie=UTF-8&oe=UTF-8Russian: африканец - no diminutive, since this suffix is at least partially borrowed and doesn't form diminutives, in the standard language any way.
Afričan, for the diminutive Afričanko sounds the best to me.
This is valid for other languages too, I believe. However, there are familiy names that derive from such diminutives, e.g. Slováček, Poliaček, Rusko, ... I've tried to create a diminutive from the theorical possibilities ("Afričanček", "Afričaník" ...) and as result, Afričanko sounds the most acceptable to me (I've found it also in Google)....We don't use diminutives of nationalities ...
Bulgarian: африканец (afrikanets) - африканче (afrikanche)
https://www.salon24.pl/u/jakelo/386365,julian-tuwim-bambo-wersja-poprawna-bo-poprawiona ;-)Perhaps, "Afrykaninek" could formally be a diminutive of "Afrykanin", but I can't remember if I've ever come across it.