I have been importing 3 defenders in the last 6 years, The first one was easy, second was was a real pain in the ....
You will not get away with a 2012 body on a td5 chassis. You can try but it will be very expensive for you!
The last one i did i used all 2011 doors etc on a 1997 110. On a galvanized chassis.
They look for the vins if you mess with the vins your card will be seized.
Its a very big risk.
You will be be better of to import a dismantled 2012 in a container as parts and build it back up in your garage on a new galvanized chassis. Then you know what to do but i am not typing that
Otherwise you have no chance! at least in BC not sure in the other Provinces but i can only assume it will be the same.
One more thing future importers always forget. Getting a defender in the country is easy! getting it insured is going to be very tough. They now what to kook for and they will not insure it if they think in away that car is tampered with or not a real 15 year old one car. I had to support my rebuild with pictures and invoices to proof my car was a genuine rebuild and not a vin swap.
But if you manage to get a 2012 in Canada let me know