Should be just fine. I am going this August with a full package. I bought the Cdn tickets for a future trip and plan to exchange the vouchers while I am there. Like you, I plan to save these tickets for a future trip. Just make sure you go to Guest Services to ensure the right set of tickets are "prioritized". For me, I plan to link mine to a different
MDE (or hopefully, not link it at all!). Many here have advised that it is best to set up a dummy MDE and move the tix there. Then move it back to your "real" MDE when you do want to use them. Sounds safer to me since I have heard of horror stories of Disney not using the correct ticket.
Can't you just buy the Cdn tix separately? And then just book the room-only package? I did notice when I priced out some summer room-only promos that the Cdn tix was no longer showing up as an option to select. I don't think its a big deal though - just buy them separately.