As for mudding to make it even i would not even attempt it.
Mudding a wall before tiling.
Prime to seal it and let dry.
Use even pressure and do not force the primer onto the.
Drywall sheets are a big improvement over plaster and lath type walls in older homes.
If it was just a small spot ok.
Do a precise measurement of the surface.
I would redo the wall yes more work and a delay but it is not a patch it will be right when you finish it and all those other issues you bring up will also be addressed in one instance.
Start with planning your wall tile installation.
The definition of level is expertly argued on points that range from the shape of earth to the surface s relation to the plane of the seas.
How to make a plaster wall level before adding tiles.
Poor adhesion causes texture to peel and bubble from the wall and create an unprofessional looking texture and plaster finish.
Repair any loose or cracked tiles.
Cement backer board a type of wall.
Vacuum clean and wipe the walls.
Wipe with a damp cloth to remove any remaining dust and allow to dry.
To do so make sure all of the tiles are intact and secure.
Plywood or drywall is insufficient as a subfloor because it is a permeable material that will rot away when exposed to water.
If existing tiles are beyond repair remove the tile and install a piece of wallboard in its place.
Prime the surface prior to the tiling.
Application roll on the primer the same way you paint a wall.
Sealing your shower walls is essential for tiling the surface to prevent moisture from effecting the integrity of your tile installation.
Wash the wall with tsp tri sodium phosphate or an ammonia based cleaner to remove any grease or oil.
Count how many tiles you ll need.
If the drywall dust is not removed before applying the primer the primer will not stick to the wall.
Remove the tile and prepare the wall according to the corresponding instructions above or tile over the existing tile.
Even walls covered in drywall.
How to use mud on uneven drywall.
Sand the area with medium grit sandpaper until even and vacuum up the dust.