We did thumb bolts on all bedrooms and baths. Our hardware (Omnia knobs) didn't come with the privacy option. The only way to lock the door is through a thumb latch. There is a little plate you can pop off the back to unlock them (I asked the same question!) I debated whether to do it on the children's bedrooms but didn't want to have to add them later. I figured there may be times where they want to lock their doors (getting dressed with visitors/friends in the house) . . . I think it is reasonable to do either though. We plan on being in this house forever and I know when I visit my mom I often lock my door while getting dressed as there is always a child wanting to wander in and who knows where the rest of the household is! They have locks on their doors now (just turn latches in the knobs) and they don't usually lock them, unless they are trying to get away from their brothers and lock them out (my youngest will do this occasionally!).

We've always had 8' ceilings in our kids rooms, but in our new build we are doing 9'. Mainly because large bunk beds are difficult to fit in small rooms with 8' ceilings. If you aren't doing bunk beds (or the larger lofty type of bunk beds) - you likely won't need the extra ceiling height. I am looking forward to it though and it allows for the window header to be slightly higher which lets more light in the rooms and I like hanging light fixtures that don't bump peoples heads. :) Just some ideas. Your rooms sizes are large enough it will feel great either way.

When we build, there won't be any rooms above our Master Bedroom. At the moment, my almost 13-year-old son and 3-year-old's room is over our Master Bedroom. My 8- and 10-year old's room is above the living room. Their bathroom is between their two rooms. When sleeping in, I can hear every single movement that my 13-year-old and 3-year do. There was carpet in the room which helps with the noise, but I hate carpet and put in wood flooring. If he drops something, I hear it. When he goes to the bathroom, I hear it. When all 4 of them are in one room, I can hear them. Just as this, I can hear every movement in my other boys' room when in the living room. They are very rambunctious and like to jump around. Another problem I have is that the pipe from their toilet/tub goes down the wall which is located between our living and kitchen/dining room. When they flush the toilet or let out their bath water, the pipe rattles in that wall. I know every time they use the bathroom and so do my guests. Most times it is rather embarrassing.

everyone is a different when it comes to sensitivity to smell, 8 months later is extreme for it to still smell. Ill go out on a limb here and assume you have already tried airing out the room? minwax polyurethane isnt exactly the #1 choice for many but its certainly not the worst product out there. without physically being able to observe the smell, id believe theres something else going on here. How many coats of finish were applied? and in what time frame? Have you had the refinisher back out to see what his opinion is? Im worried that if its not the finish and maybe something with the floor that going with a water bourne urethane will fail as well.