Its impossible to tell how your record will read by the time it gets into the national computer system. You said you didn't take the misdemeanor at the time, so you're then left with a felony charge that is unresolved.
Well, if you never took the option, I'd think that it wouldn't suddenly change to a mis. Granted, you could probably ask for some post conviction relief NOW, but it might not happen prior to your trip up North. Or it might happen, but it might not get into the systems prior to your trip. Regardless, as it stands now, it would seem that you've got a felony; not a mis.
Disclaimer: I wasn 11 years old 20 years ago, so I have no idea how sentencing programs back then worked.
I don't practice in AZ. IF you are able to reduce it to a misdemeanor, then it will show up as a misdemeanor. This still may restrict you from going to Canada.
Edward J. Blum