Hey Chris, as Roco said above, one way is to fit switches and dimmers behind the wall switch plate. In this way you can use all your lights including dimming them even if the controller is completely disconnected.
When I started my home Automation I was of the same principle, must work even if controller is dead. So I fitted Fibaro and Aeotec dimmers and switches and I kept the existing toggle wall switches but then later on down the track I replace those toggle switches with momentary switches. They work really well with dimmers especially.
And gave me a good solid z-wave mesh.
