The FE series is the one Nikon line that I prefer to let a professional with all the special tools work on. It's too easy to get the ASA/ISO dial out of adjustment when trying to get the back open. You can try with a dental tool that has a hook on it. Insert it into the hole, then rotate it so the hook is pointing at 10:00, then pull upward. It may unlatch. If you're successful and find the rewind shaft inside, remove the back, then start reassembling the camera with a rewind knob, crank handle with pin, washer and leaf spring.

If not, take the cameras to the repair shop and have them do the work for you.