The Well-Tempered Clavier is a collection of two series of Preludes and Fugues in all major and minor keys, composed for solo keyboard by Johann Sebastian Bach. In the German of Bach's time Clavier (keyboard) was a generic name indicating a variety of keyboard instruments.
The music heard in the Reverie is actually Reverie by Claude Debussy.
The piano player in Dr. Ford's office is playing Chopin's Nocturne in E-flat Major, Opus 9, No. 2.
When Hector and his gang enter the town, the song that plays is Tchaikovsky's "Op. 20, Act 1 No. 2," from "Swan Lake."
The pin that Logan is wearing looks like the "Hand of the King" pin from Game of Thrones. This could be because creators Jonathan Nolan and Lisa Joy Nolan are fans of the show, as they said themselves.