You can only use an iPhone 6 logic board for an iPhone 6, same goes for the other ones. They have different plug points, different power for the battery and the display. TD:LR Don’t do any board swapping unless it matches with the very same model and size.
no, you burnt the LED’s on the lights. Don’t have any hopes for that being repaired. however it could just be a blown fuse but I find that extremely highly unlikely because of the high power current going through the lights.