Welcome! Sounds like a very exciting project!
If you’re just looking for inspiration, you might look at a few of the project report quick browse lists in the community – created wiki. In particular, look at the “get started” list, the “whole house” list, and the “impress your friends” list for some of the more unusual projects. All creative stuff and should give you some more ideas of what’s possible.
All of that said, for a project of that size my first question would be “why SmartThings?”
I love Alexa. And I love the idea of SmartThings. And if you have a small budget, some good technical skills, and don’t mind a system that needs quite a bit of handholding, SmartThings is powerful and flexible and can be a great hobby. But some of the things on your list it just doesn’t do very well yet: home theaters, cameras, appliances, and anything where you’re not OK with at least one outage a month.
There are expensive high-end systems like control4 which can do all of those things very well, but they generally cost about 10% of the price of the house plus an annual maintenance fee.
There are low-end systems like Apple’s HomeKit which don’t offer as much power as SmartThings, but which will give you a much longer “maintenance free operating period” and won’t require that you install custom code to do things like manage user schedules on your smart locks.
To be clear: I’m not saying don’t get SmartThings. It’s a great system for many people. But it’s not the first choice if you want a system you can show off to the neighbors and have confidence that it’s going to work almost all the time. You can search the forums for discussions of stability if you want to look into more details. And most of the time when something fails you either just have to wait a few hours or there’s a fairly simple work around.
But it’s not like buying a dishwasher and then feeling confident it’s going to work every day for at least a year or so. They had at least one outage for every month in the last 18 or so except for January, and more if you count the times they took the system down for maintenance. (we usually get a few days notice on the maintenance outages, but you can’t refuse or postpone them.)
It’s not home automation per se that’s unreliable. There are plenty of low-cost systems, including Alexa itself, where outages are very rare and it’s quite easy to meet an MFOP of 6 months or more. But most of those have a much more limited feature set than SmartThings and they aren’t trying to add new stuff as quickly.
Again, I’m not saying don’t get SmartThings, but before you plan a whole house around it, know what you’re getting into.
I usually tell people who are just getting started to go ahead and buy the SmartThings hub and 4 to 6 Devices and automate one room that you use a lot, like the TV room or the kitchen, and then just live with it for two or three weeks. The glitches are not subtle, so you’ll know whether it’s something that you’re comfortable with while you’re still in the 30 day return period. You just need to be honest with yourself about the amount of time and effort it requires to keep the system going.
In your case, all of the advice you’ve gotten about wiring and stuff is great and will apply no matter what system you end up with. (And I would add to make sure that you get deep switch boxes where your light switches go, at least 48 mm and even up to 60 mm, just because that’s something that’s easy to do during construction and then it gives you a lot more choices down the road.)
But as far as picking a platform to plan your whole house around, I would research very carefully. In fact, if you can, I would go ahead and get a SmartThings hub for wherever you are living now and just do that three-week test and see what you think. Do come to the forums whenever you get stuck or are just looking for more ideas–The community is great and much of the power of SmartThings is pretty hard to discover on your own. It’s amazing what people have come up with, as you’ll see when you look at the project reports.