The 80 series rear and front diff housings have no cover so you have to pull out the 3rd member in order to access the items you mentioned. Unless I'm missing something....
Ahhh, that piece of the puzzle I wasn't aware of. So, you don't have an axle tube seal so once you pull the rear axle out you need a drive plate to keep the gear oil inside. Makes total sense now.
Why do anything for the rear axle housing except to just pull the axles out and stuff rags in the holes? Ain't that the beauty of full floaters?
Changing gears to the front hub, why do anything up front if you have locking hubs? I have Aisins too and if I break something up front, just turn...