You should ask for the price on a 33 month lease. They are usually less per month than a 36 month lease and you can keep the car for an additional 6 months beyond the 33 months at the same cost per month, I am doing it this way and it is really more cost effective. My dealer gave me prices on both a 33 and 36 month lease because I asked him to.
If you get to the point where the manufacturer will replace car you can keep your same loan. You just ask that the new car be substituted for the old car. They call this substitution of collateral. I did this a few years ago when I got a bad Subaru Outback. They gave me a new car and the dealer arranged the substitution. I was told it was more work and a little complicated but I was able to keep my very low interest loan.