Remember code is minimum. Mold and mildew resistant drywall can go on a bathroom ceiling. It just doesn't very often because code is for the shower wall
Yes! I see owners all the time asking "what's the cheapest x" or saying "im going to source that myself" only to complain during/after installation that something doesn't look good.
The price difference between a $3,000 and a $10,000 set of cabinets is negligible when wrapped into a 30 year mortgage, but consider just how important they are visually and how often you'll be using them (every day)