Jerry
A Working Holiday Visa is just that - a Visa which enables you to work in Australia for twelve months, subject to a number of requirements including your age. I think you can not work for any one employer for a period exceeding six months?
The expectation is at the end of the Visa you will leave Australia, having experienced and hopefully enjoyed your visit to our country.
A Working Holiday Visa is not a short cut to Permanent Residence and even if you held qualifications high on the Skills in Demand list, you would still need to go through the normal process of applying off shore for an appropriate Visa to permanently live and work here.
Considering the license conversion issues, obtaining an ASIC, finding employment etc, I think you are wasting your time dreaming of commercial pilot employment in Australia on a Working Holiday Visa.