One of the recent issues that have frustrated QF beancounters has been the massive amount of 'churn' caused by people changing types and its impact on the operation. I expect that the Sunrise aeroplane will be heavily influenced by that decision.
In that respect the logical replacement for the A330 on international routes is the 787. We have them ordered, at great prices, and can get delivery slots for them at the required time.
Domestically perhaps the 797/ MMA is probably the replacement for the A330 which whilst immensely popular on trans continental routes is probably too big and better yield available from a smaller airframe with perhaps higher frequency. Long term that probably means the 777X is the likely Sunrise aeroplane given the ability to rapidly transition crews between those types. I'm not sure if the 777/ 787 do common fleet flying though so perhaps that is a fly in the ointment.
Of course that could still go either way. If CASA say 'no' to 787/ 777X Common fleet flying but say 'yes' to the A350ULR/ A330 common fleet flying then that could swing things back towards the A350 option. It depends a bit on whether Airbus want to come to the party and offer up A330NEO/ A350s at a cost that doesn't exceed what Qantas has paid for the 787s.
So my heart wants the A350 as it'd be great to do domestic one week and then head over to NYC or LHR the next week as part of A330/A350 CFF but my head says long term QF is headed back towards being an all Boeing fleet.