Your primary consideration, between AU + US jurisdictions is how taxation is handled.

In AU, you pay $0 cap gain + $0 on foreign earned income.

In US, you're taxed on global income.

Before you consider setting up a complex web of entities domiciled in different taxing jurisdictions, contact someone like H&R Block Executive Tax services + walk through your entire money flow with them.

The Executive Tax Branch contain some of the smartest people I've ever come across.

Talk with them first + you'll likely save a truckload of taxes.