I would guess pretty much as originally intended.
So it does not feel like the drawing is on one piece of paper glued onto that larger board?
It looks good.
What (and how) are you doing to it?
Is this under glare-free glass? That stuff was popular in the '70s and is horrible. It softens the image beneath it. If this is...
Yes, looks like wear to the surface finish.
Slipware with a vengeance.
Apparently I got the relationships confused. A family of artists. John and Thomas were brothers. Frank was the son of Thomas, Herbert the son...
https://www.mutualart.com/Artwork/Rainy-street-scene-with-corner-shop-and-/B0A37C17B5627391
Separate names with a comma.