That cuts it a little too close for my tastes, but if you can get in before the park closes and to S&S then go for it.Antojitos opens at 4, which is another reason we love it. Plenty of time for an early dinner and we always make it to stay and scream. Just be sure to get there right at opening if you go that route.
Also, if you tell them in advance you plan to go over to stay and scream, they are very quick and accommodating.
I'd recommend an early lunch (11 or so), a snack, then dinner once HHN starts to fill up. During the event most places are open including Fast Food Boulevard, Monsters Cafe, Leaky Cauldron, Richter's, and Finns.Antijitos is sounding perfect if we get there early enough. Otherwise I know Finnegan's is excellent. I don't know what all is open during HHN in park though. We usually make good time but these suggestions are excellent. Giving me plenty of options depending on time and place.