The licence conversion will likely involve a full set of ATPL subjects. You will find them a bit stiffer than the US FAA examinations.
As for demand, you will not find that helicopter pilots are a current "in demand" skilled occupation, better study hairdressing or become a plumber!!
Migration can also be a complicated process, it depends on age and having an in demand skill. Best idea would be to visit first and speak with a migration consultant.
Its not impossible but not simple. Find an Aussie woman and.......oh, I didn't tell you that.