You could also do AA to NRT, and catch Etihad to AUH and then JNB, followed by BA/Comair to CPT.

I recently did TPE-HKG-JNB-CPT using CX/Comair and Etihad to AUH and connecting on to CX for the rest of the way on the return. FWIW, it was all award travel in J and booked about 2 months ahead of date of travel.