Asking the PO is a great idea.
If they cannot be found, maybe try these....Look for a photocell on any of the light posts/poles/fixtures that may control the dusk to dawn feature the PO liked, that may have failed now.
Look for any wall switch on a wall inside the home that is not turning anything on or off. Check your breaker box labels, someone may have been nice and written on the label index what circuit the light(s) are on. If they did, this can be a starting point for circuit tracing.
If there is a outbuilding that has electricity in it, they may have powered the fixtures from it also, and have the photocell for the outdoor lights mounted on the building itself.