Can't help with hotels in JNB as I avoid it like the plague. You can find info I've previously posted at this link ...
<a href="http://nonrev.net/eve/forums/a/tpc/f/740601221/m/508100...511073351#9511073351" target="_blank">http://nonrev.net/eve/forums/a/tpc/f/74060...3351#9511073351</A>
Avis car hire has normally been the best when I've been to SA.
Don't quite understand why you want CDG and LHR loads if your are travelling from AMS!!!