So me and my family are in the process of building three houses in direct vicinity of each other with the goal of living next to each other. The houses are 125 sq.m / 1350 sq.ft each, and two of them are conjoined (semi-detached but with slightly different layouts). Since we get to make everything from scratch, I took on the initiative to smarten up the living complex for us. I got to work, and I made a massive project with plans for a comprehensive system for each house. Everything is on a Notion list which you can see [here](https://www.notion.so/gslashj/Smart-Home-Trio-Plans-1ed58750b0f380a4b71afe1bf956a2ad?source=copy_link) (i hope I'm not doxxing myself TOO badly). Here are the main limitations of my project:

* My family don't really speak English very well, so everything is made with the Bulgarian language in mind (including LLMs, TTS, STT, etc)
* Redundancy is a key priority since I really don't want everyone to be mad at me, so each presence sensor also has door sensors to assist it, every light switch has a Detach Mode Sonoff relay behind it, and all 3 houses are 100% powered by Solar (with a 28kWh battery each) so I don't have to worry about power outages.
* Everything has to work offline, since the solar becomes kind of useless if a city-wide outage brings the house to a halt because the smart door lock needs internet connection to work. Matter of fact, every single smart device in the network will be connected to a VLAN with incredibly limited access to external networks.
* The house has to help the people, not get in their way. For the members who just want to go about their day, they shouldn't have to tinker with wall tablets, apps and finicky voice commands to turn on a light, while those of us who enjoy messing around should have every opportunity to improve the house as we see fit.

So I made the whole plan with those considerations in mind, and now I'm starting to worry about the real-life implementation issues. For example:

* Each house is planned to have its own network, its own server rack with its own instance of HA, however some utilities like security cameras and water inflow are shared between both houses and I'm not sure how I'm going to implement that.
* The portal door for the cars to enter the complex is planned to open automatically once frigate detects one of our cars' number plates and car makes. How will that same camera integrate into 2/3 separate networks?
* Currently I want to start working on the dashboards, automations and UI for HA, but I don't have the devices yet and it's really annoying having to set up and use a helper for each entity of every single device as a placeholder. 

  
Can you guys give me some tips on the project? Maybe some motivation, or some comments generally on the plans? Is there some catastrophic mistake I've made that I'm missing somewhere? 

My very first Home Assistant project is massive and I'm not sure what to do