Advice Needed

Ok all you self-proclaimed do-it-yourselfers --- I need some assistance. I have begun to peel the layers of wallpaper off of my bathroom walls. This was not a project I had expected to undertake, however my son so graciously started the project for me. (Input a very big HUFF there). Anyway, after spraying and peeling and spraying and peeling, I have begun to find wall. Or - kind of wall. What gets me is that each wall in my bathroom is different! Some walls actually have paint under the wallpaper! (yeah) Some walls have drywall only under the wallpaper, making for some hair pulling while peeling. And some walls, I can't figure out what it is I am finding under the wallpaper. So - I am posting pictures. If you know what the substance is that I am finding and how I can fix it and make it look like a normal wall - let me know!! Otherwise - my husband is ready to DEMO and put up new drywall. And - after looking at all these pictures, you may agree with him that this is the way to go. So - opinions - PLEASE!!!!

This is one wall. No, I did not make all those holes in the wall. That was there when the paper was removed. And yes, I do have all the paper removed at this section. What you are seeing is what is left.

This is another wall. Pretty isn't it. And yes, in this one section - all the paper and glue has been removed. This is the wall underneath.

This is under the mirror and above the counter top. Again - this is wall. There is nothing else wallpapery (new word) there. I am thinking this is probably some glue or something that is left from years ago, but what do you do with it. It is kind of squishy, but you can't remove it! Help!!!

This is under the mirror on the other wall. Notice the wonderful mud and glue (i think) streaks. This stuff is like drywall mud that is still wet - but cannot be removed - it is part of the wall. You can damage it - but it doesn't come off. What do you do with this stuff???

And finally - the first wall I started with. When I saw paint underneath, I thought, hey this isn't so bad. I can do this! But - unfortunately - this is just one wall - and not even all of it is painted!!! (And no, I have not completed the removing of the gummy stuff on this wall - yet) UGGHHH!!