MEL- DFW.
SYD- JFK is still too long. That's 777-8 territory.
I reckon the initial routes are YVR, SFO, JFK (perhaps BNE- LAX- JFK) and maybe MEL- DFW- JFK to give our punters two ways of getting to JFK. Possibly BNE- NRT to replace the A330 on that route and transfer the A330 onto the SYD- HND or variations on that theme.