It is very unusual to wire a room for mono. Speakers are generally sold as pairs and most setups are designed around speaker pairs to be used in a room. Considering the relatively low cost of speakers and wiring, it is much better to follow industry standards and have two speakers per room in a location that makes the most sense to maintain the stereo source you will be using. To make things more interesting, the mixing of stereo rooms with mono rooms will really cause some issues in your setup.
Run stereo to all rooms. Two speakers per room. About $100 (or less) per speaker pair.
Not sure if any of the rooms are 'TV' viewing rooms as well and you want to use those speakers for television viewing, but that could complicate things further.
Also in question is where you ran all your wiring to. If you picked a central location you want to ensure that it has plenty of room for the equipment that you want to use for whole house audio and plenty of breathing room. The number one killer of electronics is poor air circulation around them.
If I were building a home, I would be sure to include the garage (if you work in there at all) and outside for BBQing days.
You then need to think about how you want to control these rooms. Do you want to exclusively control the rooms from your phone? Do you typically walk around your home with your phone in your pocket? For the bathroom in the morning? Or so do you want to have local controls in the rooms which can pick a source for you easily right at the door? Or both?
There are lots of solutions an options which are out there, but you have a lot of questions which you really need to ask yourself and answer first. But, the golden rule for almost all home audio setups is to run stereo speakers at the very least.
If any home is under construction and you can wire it, then it is ABSOLUTELY one of the most unique times available to you. You can not only run the whole house audio, but you can run network cabling to all your television locations as well as to other rooms in the home. While 'wireless' seems so standard these days, it rarely reaches every corner of the home, and higher bandwidth items, like streaming television, use up that wireless path and leave the rest of the home running slower. Run wires everywhere if you can!
There is a ton more to discuss on the subject, potentially, and if you want to get good answers you will need to ask more questions and think a lot more about what you want done. I'm always amazed at how much thought people put into the color of paint they want to use but then pretend that the wires behind the wall, that they have ZERO access to after the drywall is up, is some sort of afterthought. Don't let that happen to you.
Make sure you are using nothing smaller than 16 gauge CL2/3 rated cabling. I prefer running 14/4 wiring to each room.
