I would dearly love to have one of these things, but I think everybody is looking at this thing wrong as to the whole Restricted/Non-Restricted issue. To my eye there is ZERO chance that it will be Non-Restricted, so the only thing that remains is whether it will be Restricted or Prohibited outright. Why, you ask?
When it comes to firearm classifications, the RCMP and the government have repeatedly demonstrated that they see no need to be bound by rulings that are legally justifiable, nor even rulings that confine themselves to common sense. What the overall length is will be irrelevant. Whether if takes five rounds or six will be irrelevant. Whether or not it is considered to be semiautomatic will be irrelevant.
I believe that there will only be one single factor that will be important to the RCMP when classifying the Six12.
It is DESIGNED to be mounted under an AR or other rifle. Period. That alone, and perhaps also the fact that it "looks scary" will most likely be the only things they will care about. I expect that it will be almost impossible to convince the powers that be as to ANY lawful or peaceable purpose for this firearm. Now sure, there may indeed be lawful or peaceable reasons to own one of these things, but it is highly unlikely that those reasons will be acknowledged, or at least not in any official capacity. It will be demonized as being something that is only useful if you want to make your firearm "more deadly", and like so many other "punish the innocent before they ever commit a crime" firearms laws in this country, it will therefore be labelled as something that only murderers, gang bangers and other criminals would want to own.
So with all that said, I believe that the very best we can hope for is a Restricted classification, with Prohibited being every bit as likely. That, at least, is what I predict will happen.
