Toolhead specific initialization is done at machine startup. Of course it would’ve been possible to design hot-pluggable tools into the firmware, but it isn’t there now.
The power bus for the toolhead does not have a disconnect in the controller - that is not something that can be fixed without a new PCB. EDIT: toolhead and linear modules are separated from the touchscreen, and the add ons.
I agree the best bet is going to be an aux switch. I bet it would be trivial to add some diodes so that software control of the enclosure lights could be maintained, but there’s really no need for that if there’s a switch on the outside.
Just a thought, since the enclosure module firmware has been released, it would be pretty trivial to rewrite the controller so that any time power is applied it just turns the lights on. Fan would have to be dealt with. Probably not worth is over just splicing the lights directly and removing the enclosure control box.