In my mind, the most logical control for the footwell lights is to slave them to the interior lights. This has been done numerous times and is not difficult. If you want additional control, whether to turn them on when the interior lights are off or off when they are on, a manual switch would have to be added. It could even be an OFF-AUTO-ON switch, but I really don't see a need for it.
I think the underbody lights would have most of the function you want if they are operated with the headlight low beams. The low beams turn on when the car is unlocked and stay on for a time after it is shut off. If you want manual off control you could use a relay powered by the fog lights to turn them off when the fogs turn on. Fog lights, as far as I know, only operate when the car is powered, and revert to off whenever it is shut down, so the on-when-unlocked feature would not be affected. That would avoid the need to add a switch or to run wires from the interior to the exterior, since all of the lighting control is under-hood.
I do have 1 switch for control of the underglow lights. wanted it on a fully separate control.
and the reason for turning off the footwell lighting is because its going to be bright-ish, and cops hassle about EVERYTHING around here. just want to be able to flick them off somehow in case.
So with the footwells tied to the interior lighting, would they go off when i open the door? cause id like for those to stay on when the door is opened. lol. i know, i keep adding complexity. thats why i thought dome originally. if thats too hard, interior would be fine to do.
where would you think the best place to tap both of these would be? like, actual location of the wires.
and how to i hook up the on/off 2 way switch to the underglow lights, tied into the headlights, so that when i turn them off, the headlights dont go out.
Im sure i could figure most of this out trial and error and checking continuity, but you seem to have a wealth of knowledge. Definitely easier to ask if you dont mind sharing the knowledge =)