I understand the A380 will not even make it from LAX to HKG, so I doubt you would see it on that route. Without an ability to do NA, EUR is the only other option.
Sounds like you don't understand much. How can Qantas use it to go non-stop from Sydney, or even Melbourne, to LAX?
Pretty sure that it could do HK, as it is 300nm shorter than going to Sydney.
