I would without hesitation choose Air New Zealand via Auckland.
Just make sure you are on the 767 AKL-SYD/AKL-PER, or 777 AKL-MEL.
My second option would be via Asia, with a stopover in Bangkok or Seoul
If you decide to take the Air Canada flight from Vancouver to Sydney, it will cost you $220 per person in each direction, extra on top of all other taxes, so dont be surprised if the bill is hundreds of dollars in addition to your points.