It's a little more difficult to get this visa but you don't need to to Thai Immigration at all inside Thailand for immigration matters. For people starting out that's a blessing. You'll probably need to see them to get a certificate of residence letter to open a bank account or get a driver's licence though once you get more established. And an o-a makes bank account and drivers licence easier too
Look at an non o-a in the Sydney consulate website. If you have a regular GP the medical certificate is easy. If you have no criminal history so is the police report. Then you need to show money in Australia only. I think your wife can get a trailing spouse non-o on the o-a. Then you are stamped in for a year. Yes you'll need insurance but can use Australian travel insurance now that you probably would have bought anyway.