So the cabin lights doesn't turn on automatically at night like in the 757. When I press L all the lights come on including the emergency exterior lights which I can't figure out how to turn off at all. Is there a specific way to turn on the cabin lights at night or how do I turn off the emergency exterior lights off?

There  is a control panel to control all the lights manually. you can even control the lights in the cargo hold and sections of the cabin. I'll let you find it.  ;)