To be blunt, you need to forget your wants and see what is possible.
Nothing stops travel to Australia after a PMV application, a Work and Holiday Visa maybe an option (you have given very little relevant info to work on in your post).
Medicare is available when in Australia on a valid visa after an application for a 309 or 820 Partner Visa has been made.
Registration and marriage do not remove any of the evidence requirements.
So first things first you need to see what evidence you have and then what you need to get to see what path to take.