You wrote: "The custom shower floor included a vinyl pan, mudpack, mastic...then grouted tiles. " Find out what specific adhesive was used to attach the tiles to the mudpack. There is "mastic" and there is "thinset". Some use the terms interchangeably, but they are very different animals. Mastic is a premixed product, it's thick and goopy and usually white colored. Mastic will come in a resealable plastic tub. Mastic is water soluble and pretty much every mastic maker specifies that it's not to be used on shower floors. If your floor gets wet, which would be expected in a shower floor, the moisture can soften or re-emulsify the mastic. That could be why the tiles are losing their bond and why tiles and grout are coming loose. Thinset should be used to bond tiles in a wet environment. Thinset comes in bags as a dry powder. You mix it with water. Thinset is portland cement based, so it cures hard like cement. Once cured, water has no effect on it. If mastic was used, that's dreadful. One other thing again based upon your description: Your vinyl membrane below the tile should have been installed on a sloped mud bed so the membrane itself is sloped to the drain. That's a building code requirement under the IRC. In general, the main components of a shower floor from bottom to top should should be: subfloor, then sloped mud, then the vinyl membrane over the sloped mud, then another layer of mud on top of the sloped membrane, then tile. If the membrane is flat on the subfloor, that can result in the membrane holding water and your floor staying moist. That moisture would exacerbate the problem if mastic was indeed used.

I don't think it could be mudjacked enough to get proper slope, might have to demo and repour. You can save a fair amount by doing the demo yourself, rent a demolition hammer for the day and have at it. Start at the edges and work your way in. I would recommend the 20 lb Makita over any of the heavy 65 lb hammers so you don't wear yourself out. Then your going to need to increase the amount of dirt around the house to get proper grade before a repour. Pavers with a slope away from the house are a better DIY option than concrete pads if hiring out isn't in your budget. I wouldn't recommend doing concrete pads DIY, too much weight and labor, might hurt your back, too hard for one person unless you have a family with multiple men able to mix, pour, level, in a timely fashion and have experience doing so.

Denice, after you repaired the drywall, did you apply any spray on texture? I'm going to guess no. whenever you patch and skim drywall, it has to have a texture coating or you will see the outline. Looks like you should have skimmed the joint a little better too. after skimming, apply this wall texture spray. you have a very fine orange peel I use this. practice on cardboard until you get the right texture that is on the wall. feather it on the wall and overlap the good/new areas. you'll have to prime once it dries. then paint again couple of videos on how to do it 1st video is pretty good. tells you how to patch from start to finish, and how to use the texture https://www.youtube.com/watch?v=FonedKgrP5U https://www.youtube.com/watch?v=3iCBEHpkro4

Since you are new to this, if you are choosing a tile bathroom, please go to utube and videos, showing proper water proofing, so you dont end up with a moldy mess, 6 months after it is all done. When you interview contractors, ask them how they waterproof a shower, and write down everything they tell you, before you pick a contractor, and look up everything online, so you know it is going to be done correctly. A bathroom, can be quite expensive. Make sure you are picking the right contractor for that job, so its done right, and your money is spent wisely. On this forum, there are way too many coming here, wanting to know about the mold in their bathrooms, and the walls that are rotting, etc, and those bathrooms, sometimes are pretty new, but, were not done properly to begin with.