MartinCh, You are lucky on the ID front that your pilot licence has a photo. The only other one I have heard of that has a photo is South Africa. This little bit of bureaucracy alone caused a lot of problems for people wanting to to come to Australia and fly.
One other form of secondary ID that is not often used is the verifiable reference. Is there anyone in Australia that you have known for 12 months or more? If they can provide their primary and secondary documents with a statement that they have known for 12 months or more, that also works.
The validity is taken to the last day of the month, two years from the month the security clearance was issued. The best possible outcome being a clearance issued on the first of the month and therefore expiring on the last day of the month in two years time. Used to be the last day of the prevous month.
Feel free to PM me for specific advice when you come over.