Kristi Goncalves' daughter Kaylee was found stabbed to death on 13 November, with no suspect yet identified.
www.bbc.com
So the video shows the girls likely drop off going past at 1:45 and then the white vehicle is seen between 2:45 and 3:15am. From this, I think we can say that M and K were not followed from the food truck or anywhere else, for that matter, as the car shows up a least 1 hour if not longer after they were brought home.
We also know that X and E returned home about 1:45 and they also were not followed.
Five-hour gap in victims’ movements still unexplained weeks on from Idaho murders
From your linked article:
"Francetich said he also noticed what looked like a sedan traveling west toward 1122 King Road at around 1:45 a.m. then head back toward the highway a few minutes later. " (Likely M and K's ride from the food truck.)
"The car, which Francetich described as both "white" and "light colored" traveled west on Taylor Road sometime between 2:45 a.m. and 3:15 a.m., he said. Only a side view of the car is visible in the footage."
This indicates that, the house or one or more of the occupants were targeted by someone with a plan to kill them. Whoever it was knew where 1122 King Road was. It's not like someone randomly ran across one or more of these 4 people and decided, for some unknown reason, to follow them home and commit murder.
I'm trying to layout what happened in an orderly fashion here to understand the sequence of events.