The rules of the Oneworld Explorer ticket are
here
Your itinerary is:
JNB-xLHR-xLAX-SCL-LIM-GRU-GRU-EZE-xJFK-xLAX-SYD-PER-HKG-NRT-DEL-xNRT-SIN-xLHR-JNB
MAIN POINT
Rule 4(e)3 states:
(e) Only one intercontinental departure and one intercontinental arrival permitted in each continent except as follows:
1.
2.
3. For travel to/from or via Ghana, Nigeria, Kenya and Uganda two permitted in Europe when one is a transfer without stopover between Ghana/Nigeria/Kenya/Uganda and another continent.
You have two arrivals and departures for Europe
At least one of these MUST be to or from one of the countries listed
Neither of yours are
Other points:
- what do you mean by GRU-GRU?
- your JFK-SYD flight is just that - no need to show xLAX, if you do show it then the tool will probably consider it an extra segment
- there no longer is a OW flight GRU-EZE (BA used to fly it, but stopped some time ago)
- one of your two entries to Nth America can be a stopover (you have two transits) - as can be your entry to Europe (the one that does make use of the exception quoted above)
Happy planning
ps I just plugged to following into the online tool:
JNB-LHR-LAX-SCL-LIM-GRU,EZE-xJFK-SYD-PER-HKG-NRT-DEL-NRT-SIN-xLHR-NBO
The only flights I selected were: EZE-xJFK-SYD and SIN-xLHR-NBO
the tool shows it to be a valid itinerary