During the auction where the mirror is sold the auctioneer mentions that the mirror was acquired from the Levesque Estate. WWE Superstar HHH's real name is Paul Levesque and WWE Studios is one of the producers of this film. This is, however, just a strange coincidence... as WWE was not involved with the film at all until after it was completed and had already premiered at the Toronto Film Festival.
Garrett Ryan, the actor who plays the younger Tim, is in two movies where he senses his future, older self. The first, is this movie. The second, is Insidious: Chapter 2 (2013) where he plays a young Josh.
Most of the pictures in the house show either reflections or water. For example in the upstairs hall there is a black and white photo of a lake reflecting some trees. Another picture shows two identical white boats.
The trivia item below may give away important plot points.
When Tim is watching his younger self watching a cartoon on TV (about 1:08:12), the TV becomes filled with static and there are several "blips". If you slow motion during that scene, there are three pictures: 1. A close up of adult Kaylie; 2. Another close up of adult Kaylie; 3. A close up of adult Kaylie with her mouth open (as though she is screaming)