1. yes sealed bearing. 2 Axle seal is in tube behind Bearing. 3. no repair bearing that I am aware of those are for a bearing w/o an inner race. 4. I always replace both outer axle bearings all seals inspect everything and new fluid with every unknown rear that has sat for a long period unused. 5. Physical as well as visual inspection. The carrier and pinion Bearings last a loooong time as long as there is no water and proper lube. Also check your vent, it is on top of the axle tube. I usually find them stuck on old cars which will push the fluid past the seals when at speed.