Also, it's like that if the NP thought they were going to lose a war, they would withdraw to what is now the Western Cape province, which had the highest number of whites and coloreds and continue on as a rump South Africa after expelling most of the black population. I imagine it would be in a similar position to Israel.
Very unlikely, people talked about creating a white majority province but to do it would require moving the vast majority of the white population and completely destroying their way of life which was (and is) dependent on masses of cheap black labour. You won't find many white janitors, even post 1994. You'd need the NP to establish a totalitarian regime for white people and that's ASB.
Were the ever present threat of international sanctions one of the big things that forced moderation throughout the transition?
They played a significant part in changing attitudes.
In 1980 with minimal sanctions, secure border and a hardline still economically communist ANC majority rule meant: white property being expropriated, a command economy, possibly Uganda style expulsions etc. while Apartheid meant the highest white living standards in the
world (higher than whites in the US), strong economic growth and 18 year old males spending 2 years in the army where they probably wouldn't get shot at.
By 1990 with sanctions impacting the economy, the Soviet Union collapsing, war on the border and the ANC reforming majority rule meant; white property being secured, renewed economic growth in a market economy, no expulsions, and whites continuing to enjoy a 1st world living standard. While Apartheid meant ever more international opprobrium, war on the border and in the townships with more and more middle aged men being called up for reserve service, white living standards stagnating etc.
Naturally whites opted to stick with Apartheid in 1980 and dump it in 1990. But change a few details, for example stop the ANC reforming, keep the Soviet Union going and soften Western sanctions then suddenly majority rule is looking a lot less attractive.