I see lots of value in many of these items, but.....a lot of work and time will be involved. You stated that you and your friend are 3 railers. My suggestion would be to buy what you want.....contact one of the big auction dealers.....and consign the rest of the entire lot.
You will benefit....the owner will benefit.....and the hobbyists at large who wish to restore, clean, and rework those fine old models, will benefit. You would be a good steward of these antiques for the 2-rail O Scale community. Tom in PGH