How will FA provide content after this season ends in June?
Eight months of offseason is a mighty long time till Feb '22.
Heard about an extended Australian Cup (ffa cup) from September and a pre season comp in January. I hope it works out well during the next offseason as we transition to a more traditional Winter season.

I don't think a winter league is a fait accompli. I suspect this 'hybrid season' will be a decisive factor of whether season will move. However, your timeline looks right with the Australian Cup final having been hinted as mid-November.. 

The 2022 season then becomes interesting. If it does become a winter league will there be expansion and a true home and away? A 26 round comp whether there is expansion or not (given 2022 FIFA dates which may change) and given a World cup in November 2022. It could start in late February - early March pause on FIFA dates  and finish in October with plenty of time before the FIFA Release date of 14th November for the World Cup.