Very similar subset of my 2002 trip. We hit the same spots around Cape Town plus Robben Island and a wine day in Stellenbosch.
The Sabi Sabi and Mala Mala areas are adjacent to Kruger National Park and part of the same huge ecosystem. We spent two days at Kirkman’s Kamp in Mala Mala, likely similar to Ulusaba in Sabi Sabi. This was at the end of the trip and we also drove back to Joburg via the Potholes and Blyde River Canyon.
And in answer to ChrisC’s question yes you should choose one of the private camps in those regions adjacent to Kruger. The private camps are big $$$ but they are allowed to drive off the roads, and the guides are in radio contact to alert to the most interesting wildlife sightings.
Also Kruger has been a preserve since 1898 (named for last Boer president) so the animals ignore the safari vehicles and you can get close up views.