Interesting topic, but I think you're definition should be narrowed down if you're gonna bring this kind of discussion up.
Basically, you could just say everything that is "outside in the weather" should be saved. That means every pole sitter, outside display etc. must be rescued and brought inside for eventually the will fall apart.
I'm not sure what you mean by "must be saved"? You list many airframes that have been already been "saved" or are in containers. (ie: Walter Soplata's aircraft and the Egyptian P-40 come to mind.) Just because they are in the woods or a container doesn't mean they should be "saved" again. Walter SAVED those aircraft years ago. The family is slowly letting them go. It may take a while, but they'll get there. The P-40 in a container is already "saved", as it's in a container. It's importance is known, but we just don't know the details of it's future.
Most you mention should be recovered and preserved or restored, but many places have a tough time keeping the ones they have in proper shape. I'd like to see most of the ones recovered, but I'd really like to see the Sparrowhawks and the Boeing flying boats back on dry land.
Don't get me wrong, I'm all for saving everything, it's just a daunting task.

Jerry