Adding onto this theory, here’s some facts that we know:
My theory: The girls went out and went to the food truck together along with the man in the hoodie. I think it’s very possible that “Hoodie” man is actually “Jack.” It’s very obvious they had all arrived together, and to my understanding one of the girls had been romantically involved with a Jack. Therefore, “Jack” has a conversation with another man in line, that then signals “hey the girls are leaving” when they walk off. Jack follows.
I think that right as they walk out of camera frame, they all three caught an Uber back home, likely because Jack lives nearby and just needed a ride back, or maybe he rode back to hang out with the girl he was romantically involved with prior to the incident.
Since Xana/Ethan were not with Kaylee/Madison at that time, I am going to assume they had arrived on the property first and fell asleep in bed together. It’s likely they were either killed first, before Kaylee/Madison got home, which means the killer was on the property by the time they had arrived from the Uber — or they were killed last, because they had arrived last and witnessed the murderer leaving the home (they would have to know the murderer to feel comfortable interacting), and the murderer stuck around long enough on the property to kill them in bed.
After Jack/Kaylee/Madison got dropped off by the Uber, a bunch of things could’ve happened, but the biggest question is: why did they call “Jack” separately so many times? If they had all arrived at the house together via Uber, the only reason for them to call him that many times was if he had left the property. I think there’s a possibility that the girls called Jack for help after seeing Xana/Ethan slain in bed, or maybe they had interacted with the murderer — however, realistically, if I were the girls and saw Xana/Ethan dead, heard something or interacted with the murderer, it’s unlikely for me to want to call Jack for help because he is nearby. Fight or flight/calling 911 wins that argument, plus the timeframe of calling Jack between ~2:30a-3:00a doesn’t add up.
I believe that maybe Jack had arrived on the property with them, and there was some kind of confrontation that caused Jack to want to leave, which resulted in him walking home and the ladies calling him numerous times. I do believe Jack is the murderer, but I’m still trying to sort out the actual possible interactions that may have happened on-site that led up to quadruple homicide. Open to suggestions.
TLDR; Hoodie man from the food truck is Jack. Jack caught an Uber back home with the girls, Jack was called many times after leaving the residence due to a dispute, and may have led to the murders of Xana/Ethan after they had witnessed him leaving the property. The roommates and a possible stalker had nothing to do with the incident.