Man you all are fast. I'm like 4 days behind, so this may have been covered, but what if the shadow was someone getting out of the truck, but not Gannon? Or someone walking to retrieve something from the back seat coming from the house? Shopping bags or whatever. I don't know how tinted the truck's windows are, but I'd imagine a smaller person in a stocking cap wouldn't be that identifiable on surveillance footage through any window.
I'd like to know if anyone took the parking spot on the street that was left empty when the truck left. Specifically a white vehicle that was of interest to LE according to the back to the camera interviewee. And if so, when it may have happened.
I find it nearly impossible to comprehend LE NOT releasing video of Gannon leaving the residence by himself, with a friend, or with a stranger. If nothing more than the public to see what he was wearing, his gait, or in the event of a kidnapping, the kidnapper. Strangely, LE hasn't released footage of any strange vehicles driving in the neighborhood around the time Gannon went missing.
I'm solidly in the camp of more than one person involved, but not convinced the other person realized or realizes it.