I m not sure I would bother with Y on this route as well, especially flying AC. Your points will cover at most $300ish of the base fare.
If you are willing to go via SFO/LAX, as you can see the connectors will be a problem, and unlikely to open up.
Also, even though it doesnt show up on Aeroplan, you can still go via SIN on SQ, but you have to piece things together.