Trivia: During the opening of the film, Lindsay Seim portrays the younger Elise in the flashback sequence. However, Lin Shaye, who plays the older Elise, dubbed over Seim's dialog in post production. Director James Wan stated that this was done because Shaye has such a unique voice, and thus, it allowed her presence to be felt early in the film.
Trivia: When Specs and Tucker go into Elise's home, the painting on the wall is from Paranormal Activity 2 and 3.
Trivia: Very briefly in the film, you can see a computer wallpaper image with the characters Specs, Tucker and an unknown third man. This third man is actually director James Wan in a small "blink-and-you'll-miss-it" cameo.
Chosen answer: The third movie was a prequel to the first 2. It was done to set up an explanation in case they made another movie that takes place after part 2, so her appearance after she died made sense.