I just went looking and found this from last years event. 5P is earlier than S&S would allow entrance. Looking forwad to more details on this.
And on September 23, 24, 30, and October 1, Premier and Preferred passholders for Universal Orlando can get early admission for the passholder and one guest through an exclusive passholder-only entrance at Universal Studios. Inside, passholders will be able to access The In Between and The Forsaken haunted houses from 5-6:30pm and the Nevermore house as early as 5:45pm 6:30pm, before the general public is admitted. These houses will be located near the back of the park, by Woody Woodpeckers KidZone.
Passholders will also receive early access on those dates for the first showing of Bill & Teds Excellent Halloween Adventure, on a first come, first served basis. Its recommended passholders show up at 30 minutes prior to show time.