It will be interesting to see what happens to the US NGAD program export wise before Australia commits to buying any Tempests, after all the US stopped the export of the F-22 to friendly countries.
It was widely reported at the time that if the UK had approached the US and requested F-22 that it was likely the US would have sold it. It wasn't going to happen of course as Typhoon was underway, but there were issues around Typhoon at the time, particularly with the German commitment and delays as a result. I think the US would have sold it to the UK, and it follows then that Australia would have almost as good a chance to get their hands on it, same with Canada. All Five Eyes, Anglophone and vital for US defence. All tend to turn up for a fight as well.