Using AM's website as source of truth, using my sample dates above, Dec 24th - Jan 1st, the only one with $1162 USD from Eastern Canada when you get to payment is
AM637
AM14
AM15
AM636 (evening dept) or AM611 (morning dept)
Use the multi-city booking option and click any options left, everything else will jump up to $1500 USD or higher, which in case it's no longer worth getting for most. I'd use AM's website to validate the pricing and book on Expedia for 24 hour guarantee.
If I find anything worth picking up from YVR/YYC I'll update the post.