So you are looking to fly SIN-XXX-CPT/JNB-XXX-SIN and asking for recommendations for XXX?
Sorry, but your original post hardly implies that, it is very vague about what you are looking for.
I don't see how EF helps you here, nor how this is related to the SAA forum really, the only "in between" place you can go with SAA is HKG, which is not really in between.
I think you are better off starting this SA excursion out of DOH, fly to JNB and form there book a r/t JNB-XXX-CPT to some African destination.