Canada is pretty massive, but what some people don't realize is that ~18,000,000 people live in a bunch of cities that are pretty much in a straight line (Windsor to Quebec City). This detail will be important later on.
My boyfriend and I live the ABDL lifestyle pretty much 24/7. He's diapered whenever he isn't at work, and I'm padded all day every day. Long story short is that we've met a rather large number of other ABDLs in the time we've been together. Some people don't realize that there is a pretty large community outside of fetlife. One group who are our best friends when it comes to ABDL stuff is this "family" that consists of an older (both male, early 40s) married couple and their little (male 22). They have pretty high paying jobs and as such can afford a rather large cottage on a big piece of land.
This cottage (more of a ranch really) is from top to bottom an ABDLs dream. It's got a giant daycare-like playroom in the basement with two changing tables stocked with padding. The middle floor and upstairs are bedrooms (adult rooms and little rooms) and a few "big" rooms that are, as you may have guessed, meant for the daddies, caretakers, etc. In the yard they have an adult sized playground that has pretty much everything, including those adult sized special needs swings that some parks these days have. They have a get together there with around 8-10 people around twice a month which usually lasts 3 days. A few times a year though they'll have 20+ people there. From experience I can say that you legitimately feel like a small child when you are there. The other littles and I will be downstairs playing video games or playing with toys while most of the adults are upstairs doing whatever it is that they do. There's usually 1 or 2 adults downstairs watching us and joining in on whatever it is that we are doing. Every 15 minutes or so one of them will go around and do diaper checks.
Most play parties have rules like no-messing, no public changing, or other things like that, but those rules are mostly for public parties. Since this is a invite-only private affair the rules are super minimal. Messing is encouraged, and pretty much mandatory for littles since the potties are off limits to us. Changing is done out in the open all the time.
Now, back to my original comment about Canada having a ton of population living in a bunch of cities that are in a line. There's an annual play party at their cottage during the summer that usually lasts two weeks and gets around 35-40 people on the weekends, but during the week there normally is around 15-20 people there. They let people park RVs there, but most people just sleep in tents. Being a bit South of Ottawa the cottage is at most a 6 hour drive for anyone in that line of cities. I see a lot of people complain about living in smaller cities and not having an ABDL community near them, but if you are willing to expand your search to nearby cities you'll be able to find a decent group, I'm sure of it.