Because I was a journeyman plumber (on new construction) for over 10 years, one of my favorite jobs is the Pre-drywall Inspection. I like to see all the different techniques and styles builders use and how they differ from one another. To keep it simple I'm just going to focus on some plumbing issues that should be addressed.
1. The 2nd picture shows an arrow pointing at a 3" abs drain pipe in the ceiling trusses. This is the main drain coming from the 2nd floor master bath. Do you notice how it looks bowed? It is, the picture doesn't do it justice. The sagging in the middle will cause solids to collect there and lead to potential block up. You will get to know a drain cleaning company well.
2. The 3rd pic isn't as crucial because it's a vent pipe(not a drain pipe) for a laundry room. You can see it has a lot of slope. This should only have a 1/4" per foot.
When I instantly see these items it concerns me what else I will uncover.
These are good things to be fixed or at least documented before it's too late and the sheetrock is up!