If you pause the episode around 4:16 when Lilly opens Rainey's case file, the "police report" in the file is actually the script for the next scene.
The reunion in the episode does not fit the timeline. The start of the school year is in September 1997, which means that seniors like Becca and Casey would graduate in the summer of 1998. Yet their ten year reunion is for the class of 1997. Celeste, like Rainey, is a junior in the beginning of the episode, so she wouldn't graduate until 1999, yet she's at the reunion, too.