The only problem I see is the visit to MRU
It falls foul of the rule:
ONLY ONE INTERNATIONAL DEPARTURE AND ONE INTERNATIONAL ARRIVAL TO/FROM THE COUNTRY OF ORIGIN IS PERMITTED
You are starting in South Africa, so when you leave it to go to Mauritius you cannot re-enter SA until the end of the trip
Can you start from somewhere else in (near) Africa, such as Zimbabwe or Namibia? You could then start with a Comair flight to JNB and then SA is no longer your country of origin and so you can fly JNB-MRU-JNB
You do not have to return to the country of origin at the end - anywhere in Africa will do; so you can still finish up in CPT
You itinerary in Australia is fine, I presume you actually want the surface segments because you could fly to all the points you've chosen (SIN-PER-ADL-MEL-CNS-SYD-JNB)
Finally, you are not maximising your flight segments - only one flight in Asia when you can have four!