I would call the sales person and cancel the meeting saying your not comfort with this deal. Don't discuss this deal anymore at this time. He will call back withing a week, so be Patient.
My 2022 CX5 had a license plate holder with screws/bolts in the luggage space. Maybe someone at the dealer removed them. Take new ones from a different car.
Car manufactures invest in time and testing to pick the best correct tire size for the gearing, weight and engines power of their vehicle. I seriously dough any guesses by a home owner will improve that.