I'd archive my current setup and then start a new one, but port over config as needed.
A bigger question is, what about the hardware? Generally once is supposed to include anything hardwired with the sale of a house but I can't really see a new owner wanting a bunch of custom IoT stuff tied to wireless instances and a control system that no longer exists (and neither would be giving them your Linux controller and router likely be great).
In my place I'd probably end up having to pull a bunch of smart switches and plugs that are running custom firmware and replace them with their "dumb" counterparts