I had that exact pink and brown tile in my last house. I must have tried 10 different decorating schemes in there; the pink is hard to coordinate with. I ended up replacing the vanity and used plain white 4x4 tile on it. That looked okay, and might look okay over your shower surround. A little awkward, but okay. I could also envision just using some sheet formica up there, well caulked; if you want to do something cool, get "boomerang" or some other 50s-inspired pattern and play up the kitsch factor. I discovered that it was going to be a big challenge to replace the bath/shower fixtures (mine were brass, very corroded - ick!). It sounded like I would have to rip out tile to get to the valve and plumbing inner workings, as you can't just pop on new handles and tub spouts very easily. But you can replace the shower head relatively easily. As far as figuring out whether it's structurally sound, I guess I'd go into the crawl space and try to inspect the floor under the tub and toilet. Poke at the wood with a screw driver and see what happens. If you replace your toilet, you'll have a chance to see if any horrors lie underneath - in mine, the subfloor was not in great shape (thanks to a previous owner who liked carpet in her bathrooms :) If you don't see rot, I would guess your bathroom will last a long time. I've read in the New York Times that tile from the 50s was made really strong. (I'm attaching a fun link you've probably already visited, but just in case...) Here is a link that might be useful: Pink Bathrooms

Hope finding the brick above gives you a little peace of mind. Years ago, (dating myself) we had an oval shaped cast iron wood burning heater downstairs and a metal shelf hung between rafters in the ceiling to hold brick above the ceiling and thru the roof. The triple walled pipe attached to the back of the heater took the smoke from the heater to the brick. Covering that heater and pipe with the least possible brick or stone -- least possible expense -- would likely have resulted in a triangle shaped chimney. That is why I suspected you may find a wood burning stove or fireplace insert and some triple walled metal pipe beneath the stone -- but you may not be able to know for sure unless/until the stone is removed. Even if you eventually discover you don't like the look of the brick behind the stone downstairs much or any better than the current uneven stone, it would be easier to clad "straight/smooth" brick with something you do like than to try to alter the current stone. Also, without the stone adding to the size of the fireplace, it is likely there would be less of the floor to redo to match your new flooring. Looking forward to the "after" pics when you make your home/fireplace what you want it to be.

Oooh, thank you @Marylee H! It is quirky :) I think painting the walls and ceilings one color is a great idea! A couple of your inspiration photos even have sections of wallpaper and tile which kind of represent my wood paneling, which I'd like to keep. I definitely see what you mean with a simpler fan too. Thanks so much!

I always use bright white for ceilings due to this color helping to add light into a room. I then opt to get my ceiling "color" from the light fixture, which gives me what I believe is more freedom to choose what I like, rather than what's "recommended."