A body 8 3/4 questions

Get the pumpkin apart and have it tanked. That will clean up most of the rust on it and also give you an opportunity to inspect the internals. Tear the SG down and tank it too. The cone SG is pretty easy to rebuild.

Gears are hard to say, might be good, might not, depends on pitting.

It will definitely need all new bearing IMHO. No way around that.

Don't forget. ring gear bolts are left handers.