Some good open Jaw fares with throwaway segments to YVR.
Example routing is EWR-HKG-CAN // PVG-SFO-YVR
Transpacific legs on UA only, but able to route creativity, try adding stopovers in Canada, Japan, Hong Kong, Korea, or elsewhere in China. Works from East Coast and secondary airports too.
Here is an example. Enter manually on UA.bomb multi city tool for $5-10 lower price than google flights.
https://www.google.com/flights/#sear...9,SFOYVR0UA316
Also the Dragonair flight from HKG-CAN should be 'missable' without canceling the rest of your itinerary, just get a boarding pass at HKG for the flight.