1)Look at defencejobs.gov.au. This will give you some idea of what education you need and medical requirements. Trying hard is great but if you haven't got the right education its not going to work.
2) Your occupation is military aviator. Which aircraft type ypu would like is taken into consideration but the needs of the Army will also be a major factor.
3) Depends on what posting you have and whether you are deployed on exercise etc.
4) If you mean posting, not really, look at the main aviation bases for ARA. If you mean away from "home" well does a bear shit in the woods. All services, particulary today, spend a significant amount of time away ( Ops, exercises etc)
5) The fussy Army aviation people are also the fussy PSA people. Again look at the above site and read the short thread on flight screening.