My gut reaction is there is no way China is setting up vehicle manufacturing or assembly in Canada because the American President would go absolutely nuts. Canada is increasing ties and joint ventures with Canada but manufacturing would be a bridge too far for our little man in the White House.
Maybe Canada inks a deal to allow Mexican manufactured Chinese EV's?
It is getting to the point where lots of countries will stop caring how the US feels about things.
Between threatening, and some actual military intervention, with Iran, Venezuela, Greenland, Canada, Denmark, Mexico, and itself the US is spread pretty thin at the moment. I think Canada will slowly open up to China and boil the frog if you will.
If they are smart about it then it will probably work out really well for them. They will need a new market for their oil, timber, ..etc since the US is no longer a reliable partner. This will take years but as long as China doesn’t do something dumb like invade Taiwan they can just sit back and win while the US is busy self destructing.
I say this as an American, also a veteran, who loves his country but hates what is currently going on.