This idea of the perps not entering the residence at all has always been a part of my theory(ies). I still find the waitress at Georges sighting of the women that night to be legit. She allegedly witnessed them talking to guys she didnt recognize and Suzie acting loud (or drunk), which makes sense since they had attended a few parties and it was grad night. Maybe Sherrill invited the girls out to eat, some guys chatted them up and Suzie smarted off to one of them, pissing them off. They followed the ladies to the Delmar residence unknowingly, parked out of site and approached the house on foot. One of them attempts to knock the porch light out to disguise their approach, but it only affects the casing and not the bulb itself. Hearing the commotion, Sherrill and perhaps the girls, go outside to see whats going on and are taken by gunpoint after some sort of fight.
Or
Same scenario at Georges, but the guys arent pissed at Suzie but instead find a way to get an invite from the ladies, maybe even followed them home without them knowing again, but this time Suzie hears someone pull in the drive after removing clothes and makeup and goes out to meet their newly found friends. Perhaps Stacy joins her after borrowing a pair of sweats from Suzie, beforehand. Some type of fight/chaos ensues that makes Sherrill come out at some point and they are all taken at gunpoint by one or more perps.
Has it ever been determined if LE could verify the girls being at Georges, perhaps by receipt or a banking statement of Sherrills? JMO's.