Interesting case, I know you all appreciate fresh eyes on these types of things. I came from a reddit post and have been browsing through the 7 (or rather 5) threads here, and this comment really sticks out to me from thread #1 based on most I've read/understand:
"here's what I'm thinking. Pretty unlikely anybody followed Suzie and Stacy home. Based on the time frame given when they left the party and arrived at Suzie's house, it makes perfect sense so I don't think they stopped anywhere in between the last party and when they went to Janelle's house. Nothing seemed outta the ordinary to anybody at the party and if the abductors wanted either of these girls, there would be much better times to do it. Which means it was directed at Sherrill. Also unlikely this was a random crime. It was somebody Sherrill knew and if that's the case, VERY odd it happened to be on a night when NOBODY was gonna be home except her. I wonder if it was common for Suzie to stay at friends houses or she was out often. It could be coincidental that the grad night was gonna be picked in which Suzie was gonna be outta town or at a friend's house. But if it wasn't, that particular night was planned, then list of suspects really narrows."
To further this, if the girls were going to WhiteWater the following day from what was supposed to be a friends house, that effectively gave the perp an even larger head start before anyone came home or realized Sherrill was missing. Which makes the timing all that more interesting... If the perp was trying to abduct just Sherrill, what are the odds he does it while the girls get home at 2:50am? What if he finished at 1:30am? Then the girls would've been the first on the crime scene. So many questions..