If he's looking for rare characters, Hollywood Studios has "Characterpalooza", which is the unofficial name for the pop-up meet and greet that feature Fantasmic characters. If I'm correct, it switches up quite a bit, but when I caught it (Fall 2016, several times between October and January), it would typically happen at 2:30 or 3:00 by the park entry, even before the turnstiles. Here I've caught: