Hi ... thanks for your sympathies! Yes ... it did ruin our excitement about getting to the gates at 6:30 am for the 7:00 am early entry. We are always late for everything and we were so excited and proud of ourselves for making it to the gates at 6:30 am (recall we never made it early again the rest of our trip because the kids were too tired). I wanted to cry when everyone counted down and rushed in through the gates and I had get out of line and head towards the ticket booth.
I "think" they will allow you to trade in your Canadian voucher ahead of time so you don't need to do it the morning of your 1st park day.
However, for safety, if you have the time, I would just go the day before your 1st park day and check at the ticket booth and see what the CM says. If this is your 1st trip, it would be a good idea to map out your plan for getting to the parks and do a "trial run" of getting to the parks. We had initially thought to take the trams in the morning but decided to walk to the parks after our "trial run" to the parks the night before our 1st park day.
Also, remember, it took the CM (and the supervisor) a very long time to find our tickets for some reason so you probably don't want to be trying to get your tickets the morning of your 1st park day as you don't know how long it will take (I got worried that they would never find our tickets).
As for the passports, I would
BRING your passports on your 1st park day REGARDLESS of whether or not you have actual park tickets OR vouchers in your hand. This is "just in case" as you do not want to be running back to your hotel to get your passports if you are denied entry for not having your passports.
Please note that we had to show our passports at the ticket booth to trade our vouchers for tickets AND that we had to show our passports at the entrance gate when we 1st used our park tickets. Those who were able to trade their vouchers at the entrance gate for park tickets also reported needing to show their passports.
Therefore,
I strongly suggest you bring your passports with you on your 1st park day. To enter your chosen park on your 1st day, you will need to show it at the entrance gate and then you may store your passports safely away in your purse/bag as you will not need to show passports again to park hop that same day. On subsequent park days, you may store your passports safely at your hotel as they will not ask to see your passports again. Consequently, carrying your passports will be inconvenient but only for the 1st park day and will be considered a minor inconvenience compared to being forced to return to your hotel to get your passports if you are denied entry.
Please excuse my preaching ... I'm just trying to help another family avoid the heartache of being turned away at the gates on their 1st park morning!
Good luck and have fun!