This may be a dumb question. With full-floating axle like that, the wheel bearings are on the outside of axle housing, the axle shafts do not carry any weight, only torque. Could you remove both axle shafts and the differential assembly without affecting the wheels or the brakes? That would reduce the total weight by 100 to 200 pounds (all of it unsprung weight), elliminate the friction of back-driving the pinion gears, and reduce the rotating inertia in that axle.
New sheet metal covers on the end of the hubs and over the pinion mounted hole would still be needed to keep dirt out of the wheel bearings.