Here's an idea. Drill a 5/16th hole in center of headlight and center of tail light then u can put single LEDs in there. Just glue them in. Also LEDs need a hot and ground
You could also mount like 4 in the grill. Just drill 4 holes smaller than the ones you are already doing
They ain't gonna light the yard up but they are bright enough to be seen if they are pointed at a wall or something