Well Arydant, it certainly sounds like you did your homework.
But if you really wanted to turn your XF into a "sporty" Jeepster to get you thru those snowy MN winters, I think you could have done so for a little less money.
Now I'm sure "Gary" from Tire Rack has a great deal more expertise in this area than I do, but in my opinion, I would have gone with a taller tire with a more narrow tread.
I usually recommend purchasing 16" wheels off a Mercedes SLK320 from a salvage yard like LKQ. Then simply install 4 Blizzaks. 205/55 in front and 225/50 on the rear.
The narrow tread will tend to plow through deep snow, where a wider tire is more likely to ride on top of the snow. We are only talking about a fraction of an inch in width, so there really should be no difference between the size you picked over the tires I'm talking about. I'm just saying it may have saved you some $$.
Don't forget to add about 150lbs under your hatch. Since you have a steep hill to climb, you will need it. Good Luck