You can get bags checked all the way through, even on two separate tickets and reservations. Just show the second ticket to the AC agent when checking in and s/he can route it through onto your connecting flight. However, you should show the AC baggage check to the check-in/transfer agent of the second carrier, to ensure they accept the AC bag. [Same on the way back, albeit in reverse.] However, I don't think a single ticket can be issued to cover the AC and non-AC space, given the discount you are using. Note that this may also raise the matter of having to pay the UK customs/immigration fee of C$70 on the AC ticket, even though you are connecting on to CDG.