We don't have a ton of IoT providers built in right now but you _can_ hook up anything with an API by configuring a proxy with an API token. That will let the agent access the device without having access to the token.
Then you can ask the agent to write an app for you! It can just give itself tools to do stuff with the devices or can make a full UI.
What it looks like for different members of the family: everybody has access to the same stuff. Everything is syncced between all devices and any integrations you add are available to the other people in the household. Hopefully you all like each other.