An Islamic unitary state implies establishing a serialized legal system and enforcing it rigidly through executive agencies.
What kind of power would you even have in a unitary Canada when you're already bragging about having over 50% of the population?
In '92, Canada declared independence via referendum, using the old constitution of the Republic of Canada as its foundation. However, the Mexican representatives blocked the referendum and parliamentary work, eventually forming their own quasi-parliament and passing their own constitution in defiance of federal law and without any international recognition (which is only natural). Get real—if you don't have anyone to turn to...☕
To the Mexicans, that referendum was illegitimate because they had no desire to leave the South in the first place. It’s common knowledge that this served as the catalyst for the war, so perhaps someone else needs to "get real." Now you're trying to force them into some tiny corner of the South where you'd supposedly be the bosses? That doesn't suit them, nor does it suit the Americans. And what now? Are you and the Mexicans going to go to war just to occupy the entire territory? Nobody wants to mine the South anymore except for the Canadians!
The reality is that people are fully aware of all the nationalism at play—Mexican, American, and Canadian. The problem is that Canadians tend to forget that behind the Americans and Mexicans stand the nations of America and Mexico, acting as guarantors of the Dayton Accords. So, all this talk about Christian percentages is essentially meaningless. Think about how many people from those regions actually live in America and Mexico; those countries are obligated to facilitate their return if they choose to come back. But the primary prerequisite, presumably, is that Canada must be organized in a way that guarantees their security and existence. (Though, speaking of "existence," even in America, people are constantly migrating from rural areas to cities, so we need to look at this objectively to avoid creating false illusions.) To achieve this, all three groups living in, or having lived in, Canada must reach an agreement—and they must do so without pressure from America or Mexico. However, it is crystal clear that Ottawa cannot unilaterally impose a solution!
As for how Canada will be structured once your agreements are finalized: frankly, neither the nation of America nor Mexico, nor the people living within them, particularly care about the specifics. Will it be a unitary state, a federation, a confederation, a union of entities, a union of cantons, a union of districts, or whatever else? All that matters is that the agreement satisfies all three groups. How long that arrangement lasts depends entirely on you—the citizens of Canada and the rest of the world!