Pearl is played by the same actress who plays Maxine. The photo of her reveals that she looked almost identical to Maxine in her youth. Her special obsession with Maxine is a manifestation of her narcissism and desire to reclaim her youth, which would mean looking just like Maxine again.
When RJ gets upset at Lorraine for being in the film because she’s a “nice girl”, Wayne tells her that none of the girls are “nice.” Later on, after Maxine gets her out of the cellar, Lorraine, rather than be grateful and try to get off of the farm together, opts to hurl abuse her way and blame her for a situation that was out of her hand. This ends up attracting the elder couple’s attention, and she dies for it.
The title of the film refers to the proverbial "X" factor and the X rating or just one of the three "X" symbols used in conjuction for porn (XXX). The context of the trilogy gives the title two more meanings. For one, the title being read as one X from the XXX designation reflects it being just one of three films telling a larger story. The X also serves as a visual symbol for a crossroads or junction, and X is the film where the two principal and mirrored characters Pearl and Maxine directly cross paths and change each other's stories.
The film features a repeating editing motif where a scene transitions with quick back-and-forth cuts, flashing forward to the next shot, back to the previous one, forward to the next, back to the previous, and then forward for good to move to the next scene. This editing choice seems to be reflective of the film's wider role in the trilogy—as the film where Pearl's story ends and Maxine's story begins, X is a film that's constantly looking back and forth between the story of Pearl from the chronologically preceding film and the story of Maxine from the chronologically following film. The film looks back and forth between them before Pearl (the past) is killed and X moves decisively forward into the future with the story of Maxine.
Considering how massive the alligator that almost ate Maxine was, and how it lives conveniently close to the old couple's residence, it's a safe bet to say that they fed a few people to it.
The fact that Lorraine discovers a dead body chained up in the basement with his pants pulled down— along with various comments the two of them make—heavily imply that Pearl and Howard have held people captive as Sex Slaves, and intended to do the same to Lorraine and Maxine.
Both the dead body and the car in the lake provide evidence that the film crew are not the first people to have fallen victim to Pearl and Howard.
When the police identify Maxine from the movie footage on RJ’s camera and realize she is still alive she is likely to become a potential suspect since she was the last person to see the rest of the crew alive and happens to be the sole survivor of the massacre.
