Compression should be more in the neighborhood of 150-200 psi. I don't see how they can be 100% sure that there are no bent valves by scoping the engine. I've looked into engines with scopes myself and it's not Hubble Telescope resolution by any means. It would only take a slight bend to cause the valve to not seal against the valve seat.
Regardless, such a low compression reading means that something is leaking air. It could be rings, valves, spark plug, or something that now has a crack/hole in it.
One thing that low oil pressure can cause is lifters to not pump up...then the roller followers get loose and can fall off. Roller Finger Follower Fall Off, as it's called, can cause all sorts of damage inside the head, such as bent valves.
