How about this: Since Ford Europe is a company stationed in Europe, and is simply owned by Ford, it can be only Europe? aka, Holden, is owned by GM, but that doesnt mean it's not it's own company.
If it's called a Lotus, sell it as one.
If it's Ford Europe, it's a european company, owned by an American company. <---- therefore predominantly European.
A honda made in europe is still the same Honda, built by the same Japanese company, even though built in Europe, due to overwhelming similarity (in models, etc..) and complete ownership by Japan, is Japanese.
Acura, Lexus, Infinity: Either Canadian, North American, or Japanese, depending on wether North America is an option, or Canada, etc..
I'd thrown 'em in North America... assuming they have that listed this time instead of simply, America.
My point is simply that you can't make a generalization here, you can get picky, and specific, there just won't be any general guidelines, it'll have to be manufacture specific, and in that, will lie your answers. OR, go broad and undefined, and have faults included
OR....
A value setting would be a great way to establish this all. Example: Company owned by? 5 points Company located in? 4 points Company designers? 3 points, Company builds original cars, or simply copies? originals, 7 points, copies, 0 points. etc, etc...
This is simply an idea, as to how one could classify cars, and make no exceptions, apart from my ideas above. The only trick is deciding which aspects give more points, and less points.