Helipom,
You have asked a lot of questions...but there is really one answer.
The "gathering" of the "50" hours is actually flight training, you can't jump shop and get 2 - 3 hours here and there. You need to find a school you are comfortable with, focus 100%, and do your training there and learn how to fly.
Sure, once you have a licence, you can fly at different places around Aus, providing you can persuade someone to hire you a machine with only 50 hours of flight time (!).
The balance of your questions will be answered along the way by your instructor etc.
Learning to fly is a major task, not something to be taken lightly. Commit to the project, or don't do it at all.
If you commit, you will be a safe pilot and have a lot of fun.
Arrrj