Maybe you could look this up on Wikipedia for us?

Apartheid killed very few, 7000 is the number I can find (then 14k during transition). This doesn't square with "needs to kill increasingly large number of people". That's my only point.

It doesn't matter because it doesn't justify apartheid, just shows that you don't need to murder lots of people. Having bad countries outsource key government roles to good countries doesn't need to involve any sort of tiered citizenship or segregation.

Current murder rates seem high and are likely underreported. (For instance, Guatemala won't record a homicide if the person doesn't die right away but is helped by aid personnel.)

Further, apartheid isn't a case of what I'm proposing. They were running their own country for their benefit, not as a humanitarian/client setup.