Ah right. Not mentioned in the post. As Tod says, your trailing spouse extension follows your husbands. So, follow his instructions and change the reason to retirement extensions for yourself. :)
That's not what he is saying. Some banks have started freezing bank accounts until people prove they have a long term visa. Mostly in Phuket though, I believe.
Get a NON O before you leave Oz. That is the easiest way to do it. Then use your funds, that you already have in your Thai bank, to get a year extension of stay. If not, do as Tod says. ;)
It would matter, as he would get the 60 day extension of stay (which does not require any money). This would give him added time to then keep his money above 400k for another 2 months, and then get his 1 year extension of stay inked in. ;)
You must be married to a Thai. As Craig said, if you haven't used a 60 day extension based on family, use that. Otherwise, if your office is not forgiving, you will have to leave Thailand and start over with a new NON O.