For projects of this size, what legal/financial structure do you use? Particularly of interest for what Australians do, but any stories would be good.

When I've looked, a sole trader with liability and cyber insurance seemed reasonable (maybe $2k/yr), but a Pty ltd with the same would probably be safer ($5k/yr).

It all comes down to what the risk of being sued is though. I'm sure selling games wouldn't require this.