Tile is gone! Good thing we pulled it too (I was briefly considering just adding a cheap plastic backing to get us up to the ceiling) because it was GLUED TO THE DRYWALL.
Anyway, it’s gone now, and today if I get off my ass I will be stripping the last of the wallpaper, washing the walls, and starting the skimcoat.
The plan for the area around the shower, then, is to mortar in a waterproof membrane as a new backer for the new tile. You know, waterproof. Like things around showers should be. FFS.