It is very unlikely that AC will upgrade you however nicely you ask. Your best bet would be a Last Minute Upgrade at checkin. Checking in earlier obviously gives the best chance, costs vary. For YYZ->BOS it's probably going to be a few hundred $ - especially from Tango. There are a couple of threads tracking and discussing LMUs.

The YYZ - HKG leg, from PY you are probably looking at $1000-$1200 for an upgrade if available, but that varies, I'm just going off flights of that sort/distance from the threads.

AC pods don't lend themselves to having a chat.

Gold w/star alliance should, I believe, at least give you priority check in, Zone 2 boarding for your Tango legs, and MLL access. Make sure your number is associated!

Enjoy.