Comments, let's see. First comment, welcome to CGN, I'm pretty new myself, and since buying my first restricted (an M&P 15-22), I can tell you it's been an interesting ride from the day the transfer was initiated over the phone and the day I got it to the range (6 months). You are thinking too hard about how a firearm becomes restricted. This document amused me, because I've seen a lot of folks on CGN and IRL saying "it's banned because it's an AR", which seemed a tad too simplistic to fairly explain the classification. However, as you can see, that's precisely why it was restricted. If they had included something about a trigger or because the pistol variant was imported, I would have thought "that makes some sense", but they didn't. The ambiguous nature of the wording in the FA and in this document are something you'll get used to.
Anyway, these days the 25 round mag isn't a problem, because those who bought this rifle when it was first imported were informed by the RCMP (by lettermail) that they had to bring the mags to a gunsmith and get them pinned, then get the smith to certify that it was done. The friend I bought this from had to go through this, and he called the RCMP after receiving his letter requesting some guidance on how to transport it since it was now a prohibited device, and what would happen if he were caught with them on his way to the gunsmith. As his story goes, the officer responded by telling him to "drive slowly".
My advice in all of this? If you're looking at a little .22 plinker that looks awesome and gives you all the features of a "real" AR15 (don't believe me, read around and ask people) for a VERY reasonable price, go buy one. It's a great way to introduce yourself to the 'restricted club' if you're not into handguns. If you can get your hands on extra 25 round mags they will all be pinned to 10 rounds, and in my opinion, are aesthetically the only mag that looks like it belongs in the rifle.