You have not given enough information here to give you a real answer.
A Limited Liability Company (LLC) and a corporation are two very different legal entities and cannot be both.
A lot will depend on if you are an American Citizen or Legal US resident, even though you currently live in Australia.
But this is really a question for an Attorney and Accountant that specializes in dual nation Real Estate and tax situations.
I do work with many International investors resident outside the US, mostly from Europe and what entity they buy such investments in does differ depending on individual tax and citizenship situations as well as the expectation and purpose of the investment.
There is no one answer fits all to this question.
Kathryn Lilly, Broker
Realty on the Greene, LLC