When they first announced Limited Time Magic, they announced some kind of villain event for DHS on Friday the 13th and they said they would be open until the "13th hour". I'm guessing Disneyland got on board with that idea to kick off their Halloweentime on that day. So it's the 13th hour on Friday the 13th. I know 1 PM would probably technically be the 13th hour, but 1 AM is a much nicer closing time.
That 5 PM close the day before is extremely early. It's either some kind of Disney event (press event, most likely) or someone with super deep pockets. Might be a good time to panhandle in the Esplanade.