He/she will be fine with the tires on 20" or 21" wheels. His/her car will have export plates and all-season tires will be legal to use with that car.Possibly. Call the OSD folks and ask. I guess it depends on whether rims / tires would be something that affects the build and would end up screwing up your date.
For sure they can sell you tires and rims at the FDC because the winter driving info indicates they'll sell you rims and winter tires - put those on your car and put the other tires in the car. Are you planning on driving the car in Sweden in February? If so you'll need to do something about tires as the Perilli's on the 21-inch rims likely don't qualify for the Swedish winter road restrictions.
I see you are in California. If you are in So. California, PM me your retailer you put the order through and your order number.I have an OSD in February which I ordered an XC90 Inscription. I just passed the date for me to change options and I really want to upgrade to 21" rims. Can I do this at the factory?