If you are applying in Australia, you only need proof of funds does not need to be in Thailand.In Australia it is an O-A Multi-entry visa (Retirement).
no the time starts on the day you get stamped in at Immigration. The Visa sticker will have a valid to date on it, you have to enter Thailand prior to that date.
I can add one thing, no one at Samut Sakhon Immigration speaks English, if they do they don't own up to it, so if your Thai is not to good take a friend.
Depends on how long I am staying, short time visa exempt, longer tourist visa and yes I have extended both at different times, but never back to back. I am married to a Thai and can stay longer, or based on being over 50. But I still work and love coming and spending my time in Thailand.
I'm an Australian and have entered Thailand from 2 times a year to 4 times a year for more than 35 years, I have never been asked proof of funds, onward travel etc,. If you are entering the Kingdom on the correct visa there will never be a problem.