Some make you buy your own type rating, some bond for a year or more depending on a/c type.
Aussie ATPL subjects probably won't help much unless you put the type you're interested in on your Aussie license in which case you can fly on an SA validation. Check this though because my info is out of date.
Did you contact Paul at Solenta? He did offer and would be the guy to speak to there.
Piece of advice. Don't buy a type rating then go looking for a job. Get the job first.
Other contract operators are basically all at Lanseria. Your hours sound good enough to get a start.
Feel free to pm me. Where are you now? Do you have an SAA CPL?