Your story of renovation reminds me of a watching my mother and me (my hands and parts of my arms) and earlier my grandmother Danielson and me putting together 1000 piece jigsaw puzzles. each piece only fits one place. I used to look at sub-assemblies and then hunt out the missing piece that fitted, getting matches the hard way (trial and error) while grandma looked at what was on the piece and set it near where it probably went (and let me find more to join it) or found others that looked like they might go very near it and fit them together.
Your story of finding the linen closet door in the attic indicated that perhaps someone before the previous owner might have started a small renovation in the main bathroom-- or maybe the the previous owner started a bigger one. That is what started this thread.
You are trying to save money and economize, which is a wise thing to do. Doing that requires saving as much as possible that is already in the house for reuse, very much so. In your case, once the known-to-be-trash is gone, the remains each have a particular place they best each belong. Primer and paint best cover walls and/or ceilings, for instance. Doors each go to one frame (custom sized a lot in old houses) each. Just like a jigsaw puzzle.
BTW, grandma Danielson was a skinflint with cash-- she left a legacy of over 1 million to various Danielsons. I have not gotten mine yet. Regarding jigsaw puzzles, she owned maybe 5-6 1000 piece puzzles and rotated between them, doing them in her spare time. When she got tired of one of them, she gave it to mom. Mom gave it to me. You might say I grew up with jigsaw puzzles. :)