My guess with the coming home lights etc, you would leave the switch in auto position.
They would be connected to some kind of switched permanent live that comes on when fob unlocks, goes off when fob is locked.
Press button to open car, powers up the switch for auto lights, senses it's dark through sensor, turns lights on.
Get home, get out car, press lock button and powers down system.
You'd just need the live for the whole thing on something that switches with fob? Obviously you can't use anything to do with door mechanism etc as your lights would turn off when your anti-hijack operates