During Margot's first chat with fish_n_chips, they share what their favorite Pokémon are, Margot's being Uxie, fish_n_chips's being Kecleon. Margot states that Uxie's unique power is erasing memories, which may appeal to her own personal struggle to move past the painful memory of her mother's death. As for Kecleon, it is based on chameleons and their ability to camouflage, alluding to how the fish_n_chips account is Robert's disguise for getting close to Margot.
Detective Vick repeatedly tells David that it isn't his fault that Margot went missing or when it was discovered she was seemingly murdered. She is right because it was Vick's own son that caused Margot's disappearance and it was Detective Vick herself that framed a reformed criminal for Margot's supposed rape and murder.
By calling the cops when he goes to the lake, David may have unknowingly saved his own life. When he calls Vick, one of the first things we see her doing when the call connects is grabbing her gun. She tries to maintain a calm demeanor, but literally does a frantic double take when she hears sirens in the background of David's side of the call. A Rewatch Bonus makes her question of "Did you call the cops?!" before sprinting for her car seem less out of concern for David's mental state and more malignant concern for the cover up that's spinning out of control. She later proves she's willing to murder to protect her son. Had David not called the cops, it would have been easy for her to kill him and then conveniently "find" Margot's car and body, which she could then present as an extremely complex and tragic murder-suicide by a grieving husband who'd returned to the scene of the crime out of guilt. No one would have questioned the lead detective and the link titles displayed as David searched for info show that social media was already ready to believe it.
The same goes for Uncle Peter. When David suspects that his brother might have been molesting his daughter and is behind her disappearance, his first instinct is to call Vick, but changes his mind and decides to confront his brother by planting hidden cameras in his house to get a confession. Had he called Vick, she could have easily framed Peter and made it look like he was a vile pedophile who committed incest and murder of his niece. It would've been easy to convince the media and even David of this, because he is a weed smoker, something a lot of society and even David himself still frown upon.
There is apparently an entire alien invasion going on within the background of the film, hinted at via various news articles. Did the aliens win offscreen after the movie cuts to black? Is the Earth left in devastation? We may never know or get a clear answer.
A Freeze-Frame Bonus in Missing suggests that delegates for humanity and the aliens are meeting with each other, suggesting some tennis peace agreement was reached before anything too bad happened.
