From my understanding they plan to retire there Growler's and SH's around the same time as us (or us the same time as them) in the 2030's so I dealt the USN would want our aircraft when they would litereally have them a couple year's before retiring them..
Whilst I'm sure the USN would love to have more F-35C's available when the time comes, but I suspect, from all that I've read over the last while, the Super Hornets and the Growlers may well be kept operational well into the 2030's and possibly beyond too.
And it may well be that the Super Hornets disappear from service first and the Growlers are there for the long term, the very long term.
So for Australia, it may come down to which 'path' do we follow? The USN with the Growler for EW or the USAF, which I understand is far more likely to use the F-35A's as an EW platform (unless some future 'unmanned' option comes to light).
Anyway, still a lot of time ahead of us (the Growlers aren't even in RAAF service yet!!), it may well be that a future Government takes advice from Defence, that we park the Growlers and have the F-35A's performing the EW role, or it may be that we follow the USN model, where the Growler might have a longer life.
Time will tell!!