The actors in the Stars Hollow musical, Sutton Foster and Christian Borle (both Tony award winners), used to be married. This was the first time they've performed together since their divorce.
The picture of the man that is next to Rory's desk at the Stars Hollow Gazette, where she flips the picture frame around in front of Jess because she doesn't want him to look at her "like this," is journalist, David Carr.
The character of Stanley (the one in charge of Richard's tombstone) played by George Anthony Bell also plays Rory's Professor at Yale, Professor Bell, in the original Gilmore Girls series starting in But Not as Cute as Pushkin (2004).
Sophie offers to play her song for the play; however, Taylor tells her that the song isn't catchy enough. The song Sophie tries to sing is "I Feel the Earth Move", an original Carole King song from her 1971 album Tapestry. Also on the same album is the song Where You Lead, which was used (in a re-recorded version by King & her daughter Louise Goffin) for the theme of the show.
Sophie, the woman who offers the rejected song "I Feel the Earth Move under My Feet" during the town musical tryouts, is played by none other than the legendary singer/songwriter Carole King, who wrote that song (which reached #1 on the charts in the real world), as well as the theme for "Gilmore Girls", and over 100 other hit songs. She was the most successful female songwriter of the latter half of the 20th century.