I believe the restaurants stop serving at 4:30pm but Finnegan's is open...according to other posters on here.
S & S lets you into the first house at 5:45 so you'd be cheating yourself out of 15 mins if you ate before HHN.
Finnegan's actually let us out before 6 on Halloween (not sure of the time today because we hadn't gotten our check yet when they released everyone). Plenty of time for walk-on haunted housing both times before the big crowds hit.