When Matt asks Emily if she kept track of the unsub after 2011, and she seems uncomfortable answering before saying, "I wish I could have," she's clearly thinking of her "death" at the hands of Ian Doyle, which also happened in 2011 and forced her to go underground.
This references In Name and Blood (2007), where Eddie Cibrian was the antagonist and Mandy Patinkin, (Gideon) Thomas Gibson, (Hotchner) Shemar Moore (Morgan), and Jayne Atkinson (Strauss) were still part of the cast. Moreover, this was what marked Mandy Patinkin's final appearance as Jason Gideon.
The William Shakespeare verse JJ quotes, "What is past is prologue", is from Act 2, Scene 1 of "The Tempest".
24 minutes in, a transcript of an interview with the suspect is shown briefly. Names listed on the sheet are Judge, P.J. And Squi...any of them can testify... mimicking the Brett Kavanaugh Supreme Court confirmation.