I think that it’s more likely that the Australian Government would approach the British first to see how much the AUKUS SSN project could be accelerated with the aim of transitioning straight from Collins class to AUKUS SSN’s without any Virginia’s. There would still be some US components but this would avoid diverting any submarines from the USN.
The fact that the Brits have already announced their intention to accelerate the program does help us but, the biggest bottleneck may be RR’s ability to produce the PWR3’s at the required rate.