When applying for a Hong Kong Professional Pilot's License on the basis of conversion from a Foreign Professional Pilot's License, a license which was issued on the basis of equivalence by a foreign authority will not be accepted by HKCAD.
So in the example given, if the EASA ATPL was issued on the basis of equivalence of the African license I expect this will be annotated as such on the EASA license. In which case it won't be acceptable for conversion to a Hong Kong license.