I will try motion sensor lights. Hopefully, they don't have LEDs on them. Her room smoke alarm has an LED on it and it took me a long time to convince her that it wasn't a space monster eye looking at her. We opened up the thing so that she could see the battery and the electronics, and see that there were no space monsters.
She likes the motion sensor lights outside on the back patio. She will go out there just to turn them on. That's a good idea.
I will try the special necklace idea, too. She likes wearing bead necklaces. Maybe we could make our own and she could imbue it with powers to keep the monsters away.