Wow...I am shocked by your fathers response to what is clearly a problem that he significantly contributed to. If you are able to find one of the tile pros from John Bridge who works in your area...you would very likely be in good hands. There should be no delay in getting onto the JB site to ask questions. I think the delay is just for uploading pictures. Be prepared though because they may also suggest you need to start over if you want certainty that it is done properly. On the bright side, at least it looks like your husband has discovered the source of the water behind the wall ( it's hard to understand why this wasn't investigated by the crew that did the original tear out ). While it does not address the shower waterproofing/ material suitability issues it is at least a step in the right direction.

No-casings and painted sheetrock returns are the right look for a modern house, and the major brands of windows have all gotten on board with all-fiberglass or for Andersen, all fibrex, windows, this class of windows having relatively shallow frame depth, and all offer dark colors same outside as in, to achieve this popular new look in "modern." The #1 favorite color is black, followed by dark bronze. To do it right, the carpenter needs to properly shim the opening before the rockers get there, so reveals are consistent all around. Insider Carpentry channel on YouTube has a great vid on how to do this right. The rockers need to mask well, then use a tearaway bead at the window side, and a good corner bead at the outboard sides. The best look, IMHO, is to have a 3/4" thick sill at bottom with the same window reveal as the sides, so the bottom of the opening is not shimmed in as much as the sides. To get this right, the window sits up on shims at installation time and the bottom of the opening is only shimmed to get it dead level and flat for the drywall corner bead. That sill gets no apron under and has to have a good plate-like bed. Anything more than 3/4" looks to beefy. Sills should have tiny returns. Here is a 3D render done in Chief Architect of a window with sill and another without. The windows are modeled at the same dimesions as the all-fibrex Andersen Series 100, the wall is 2x6 framing, and the depth of the returns to the drywall face is 4-9/16". Note the very shallow bullnose on the sill edge, and the small return. A painted wood or stone, metal, or composite sill is going to be more durable and easier to wipe clean than painted drywall, no matter the paint. And as for the dust on those vertical returns at jambs, or horizontal across the head, and durability, you have all kinds of drywall corners eleswhere in the house. Why are corners at windows going to behave differently. If your builder has not done these no-casings openings before, think twice before asking him to do it. If he has, insist on seeing examples of work. You don't need to be a first time event for the builder, his carpenter, or his sheetrocker.

We built our 3000+ sq.ft. home on our land and it took 6 months from ground breaking to move in. It was totally custom with high end finishes. Our GC said that we started in perfect weather and finished with perfect weather. That's why it went so quickly. Plus, I am the world's most organized person. When he needed a decision, he had one immediately or by the end of the business day. And, I didn't change my mind. I was at least a month ahead of him when it came to decisions and finishes. What you need is a copy of his proposed schedule. Now days, these are done on spread sheets. It's not a contract, but it is a guideline. Having one will keep you off his back. But, it will make him more accountable, too. There should be something going on at the site every day. If there is a large gap in activity, start squawking about it. You should be nice about it, but you need to make sure you are a priority. You will know when it's beyond the GC's control. Still, stay on top, be part of the process, make firm decisions and ask what's next every time you have any contact with him. He will tell you when there is an expected activity gap so it's not a surprise. A lot of time it's due to wanting a particular sub contractor and having to wait. If the wait is too long, he may need to get someone else. Just keep on top of it.

I'd be inclined to suspect a combination of fan dampers not closing properly and gross overchilling of the bathrooms. Aside and editorial: I'm not a doctor, but I consider anything below about 75 deg F too much change from outdoors for good health in the summer. The hotter your climate, the more critical this is. Seventy-eight or even 80F is ample cooling when the outdoor temp is in 3 digits. It saves significant money on your summer electric bill, too. Overcooling the indoors also makes you more miserable when you go outside, because it inhibits your body's ability to adjust to the heat. As you've seen, overcooling can also cause house problems. If the bathrooms were in the 60-65 deg F range, that's excessive. I've never heard of a bathroom with more than one heating/cooling register. Is the bath that huge??? Try closing off all the vents but one. Leave the doors open when the bathrooms aren't in use. Remove the fans from their housings and check for proper damper operation. Clean the dampers and ducts thoroughly with a brush and vacuum. Lubricate the dampers (if necessary) only with a dry lubricant, such as Teflon or graphite. It sounds like the fans aren't really working all that well. I think that the 14' run to the cap is too much, especially with bends. You need a shorter path to free air. Consider ducting the exhausts straight up through the roof (example). The roof cap will also provide a redundant damper. Use rigid pipe.