1) rim is too wide for that tire. also you should find out the offset of the wheel. if you insist on using that wheel, you'll need a 255/40 tire, if not wider.
2) a ten inch wide wheel can fit in the rear - may require spacer rings and rolling of the fender wells.
3) for the front, a nine inch wheel is about the max using a 245 and some 255/40 tires (some 255/40 tires are too wide)
lowering the car is fine- just get the proper shocks and springs. a negative camber plate may help wheelwell lip clearance.