The only basing for QF international/longhaul tech crew at this stage is SYD. You can live in Adelaide if you want and commute to Sydney. So, to answer your question, you can fly QF longhaul and live in Adelaide, but you will be based in Sydney. Many do this.
The basings for QF shorthaul are SYD, MEL and BNE.
Aust Airlines tech crew are based in CNS. The initial basing for A330 tech crew is MEL, I believe.