AC flies YYZ-YVR-SYD same-plane service and has good award availability, dont know the current cost as I dont fly AC much but you can redeem UA on AC. Huge differences in award availability by day of week as well as season, always hard to get the desirable routes. If you want to use DL awards, booking KE via ICN might be your best bet esp. if you also want to visit Seoul (well worth visiting, kind of the anti-thesis to Oz/NZ).