Congrats on getting the tranny out. I did this just last month and it sounds
like had similar experiences (although my input shaft was fine).

I opted to replace the entire clutch - a good call since the old one had a
broken spring and was generally poor. Worth the peace of mind. Sounds like
you need a new input haft -- that 'welded' material may be why it was so
difficult to get things apart.

When I was removing the oil seal I had the same problem -- it just wouldn't
come out w/ a screwdriver. Went to the local FLAPS and spent the best $5 in
recent memory on a seal puller. Insert and pry - just like removing a
framing nail (although much less force required). Skip the screwdriver and
go find one.

The tricks in the archives will work just fine on the pilot bearing.

john