No, the Dole Whip stand isn't open, since it's in a part of the park that's closed.
I think that Main Street Bakery usually stays open late, and you can't go wrong there.
I got a chocolate pie at Pecos Bill's once during e-night, and it was great. Sometimes Pecos Bill's doesn't stay open the entire duration of e-night, though. Check the hours on the side outside the restaurant anytime that day. It may just be open the first one or two hours after the park closes.