How do I disable the cabin lights that stay on when any doors are open?

Unless it has the interior override switch that lets you turn them off there isn't any real way to do it that doesn't also affect the security system. That override switch basically disconnects the control circuit between the interior lamp relay and the lighting (green arrow). That prevents all of the interior lamps from coming on. You could go to the fuse panel and pull the fuse but that isn't real convenient to do on a regular basis.
I would probably opt to install a switch in the dash and run a couple wires back to the rear integration module behind the upper rear seat and splice it into the Tan wire that controls the relay. To access it you remove the rear seat cushion like you want to access the fuses, then the bolts that anchor the belts that also anchor the seat back. Now find the connector with the Tan wire, It's in connector 2 pin B5. It runs from there to the relay in the fuse block. Splice into it so you can turn it on or off as desired.