Congratulations on the new house! Sounds like an exciting project. 
If you check the community – created wiki, there’s a quick browse list in the project report section for “whole house” projects. You’ll find a lot of discussions of wiring, switchbox depth, etc. there which should be of interest.
As far as sensors, etc., at the present time the protocols that SmartThings supports are almost all limited to battery sensors. There are a few exceptions, But they tend to be multipurpose sensors which need more power and are also much more expensive. It’s not impossible to use hardwired sensors, but there are no off-the-shelf solutions for that requirement. You have to cobble things together to make it work.
For some discussion of those options, look at the quick browse list for “security” in the same project reports section. Most of those will be from people who previously had a hardwired system and are now attempting to make it work with SmartThings. Again, most people starting new with SmartThings will use battery powered sensors.
You might also want to take a look at the following thread which discusses the various device class features and gives examples of the kinds of sensors that are available: