It looks like you may apply for the visa online but should not select the US as your country of residence (unless you are granted a relevant US visa). 

I don't think it matters where your bank and pay documents are from as long as they show your ability to support yourself for the duration of your visit.

At the time of writing processing times are:
75% of applications processed within 16 days 
90% of applications processed within 26 days.

See https://immi.homeaffairs.gov.au/visas/getting-a-visa/visa-listing/visitor-600/tourist-stream-overseas#Overview