What are the requirements for the Non-Immigrant OA visa application and 90-day reporting in Thailand?

I have been working here in Thailand but the work is finishing so I intend to return to Australia where I may be applying for a 12 months multi-entry Non-Imm OA (based on being over 50 years) in Australia (Canberra). I know I will need to show equivalent of 800,000 baht in a bank account (seasoned) which can be in an Australian account.

My questions are:

1.When doing my first 90 day report will I have to show those funds still exist...if so, can they still be in Australian account or do they need to be in Thai account.

2. As it would be a multi-entry, would I actually have to report at all if I never stay in the country for a full 90 period at a time or is it different for this type of visa?

3. I gather I can extend my stay by almost 12 months by leaving the country and coming back in near the end of the first 12 months...is that correct?

I think with my financial circumstances I prefer to apply at the Australian Consulate, hence the clarification required on 'show of funds' once back in Thailand.

Not sure yet where I will actually base myself in Thailand upon return.

Thanks in anticipation!