The Mafia families in Canada are very diverse. From what I understand the 3 main cities are Montreal, Toronto, and Hamilton. Here's my guess on who's active:

Montreal
The Montreal Mob is probably a single family with two rival factions, Sicilians vs Mainland Southern Italians (Possibly Calabrese for most part). Though I think the beef is more about Rizzuto loyalists vs those who favored the old Cotroni regime. Either way I think the Montreal Mob is probably like the Chicago Outfit rather than your typical American LCN family. What I mean by that is they probably don't make guys the same way the LCN families do, and there are significant non-Italians in the group as well. Also considering the current leadership and their ties to Sicily, this family has strong ties to the Cun trera-Caruana Sicilian clan and I'm sure there are blood ties, this connection is what makes the family very powerful. Currently the Montreal Mob is under the control of the Sicilians, there's a new young leadership with Stefano Sollecito as the emerging boss. This power may be questioned soon when Arcadi and his two lieutenants, Del Balso and Giordano are released from jail, or perhaps not, we'll see what happens.

Toronto
Toronto is known to be controlled by the 'Ndrangheta clans for most part, while people do hear of the Siderno group, it's very important to understand that this is not a family, but rather a commission like body that was assembled to settle 'Ndrangheta affairs and disputes. From what I know there are about 7 or 8 'Ndrangheta families that operate in the Toronto region and they all have ties back to Calabria which makes them very powerful. There are also Sicilian mobsters operating in Toronto, the Cun trera-Caruana have presence there, also the remnant of Paul Volpe's crew (Former soldier of the Buffalo family), apparently this crew is headed by Peter Scarcella. The Sicilians in Toronto are obviously Rizzuto allies but I also hear that some of the 'Ndrangheta clans in Toronto are also Rizzuto's allies, while some of them are enemies.

Hamilton
In Hamilton you have the Musitano family, their origin is Calabrese but they are neither LCN nor 'Ndrangheta, yet they're respected and acknowledged in the underworld. My best description of them is they're like a glorified crew of some sort that was built in Canada rather than Italy. The other family is known as the Luppino family which from what I know were associated with or even part of the Papalia crew of the Buffalo family. The Violi brothers are in the Luppino family and if I were to take a guess, I would say the old Papalia crew is pretty much what the Luppino family is today, in other words they're the same family. I also know that these two families are rivals, the Musitanos being Rizzuto allies while the Luppinos are against them.

The biggest game is Canada is who controls the narcotics, and ultimately it's probably a bigger battle between the Montreal Mob and the 'Ndrangheta families of Toronto.