So... you want to lease the car in one country and drive it for 2 years in another country, right?
how were you planning to handle auto insurance for the car? which address were you planning to give the insurance company (us or canada)?
when you take over the lease what address were you planing to give the leasing company? which bank account were you planning to use.
when you drive across the border with this car the first time, when the border agent asks "anything to declare? purpose of the trip?" what answer are you planning to give?
i think if you answer these questions, the answer will become clearer to you.