Cordelia sings "The Greatest Love of All" by Whitney Houston, a song she chose to sing for the talent show in The Puppet Show (1997). Her performance this time around is equally terrible.
After looking through some past photos, Cordelia said "yikes" when looking at a photo of her hair when it was first cut short in The Shroud of Rahmon (2000). This is an inside joke as Charisma Carpenter disliked this specific haircut, as stated in the Season 2 DVD featurette.
The title and Lorne's comment about "slouching towards Bethlehem" is a double-reference; partially from the book by Joan Didion of the same title, as well as William Butler Yeats' poem, The Second Coming ('And what rough beast, its hour come round at last, Slouches towards Bethlehem to be born?').
When Cordelia read her yearbook, it contained references to the school "burning down," the "giant snake," and "flaming arrows." These events all occurred when the Sunnydale High student body fought The Mayor in Graduation Day: Part 2 (1999). Both Angel and Wesley were present for these events.
Gunn asks if Cordelia wants to know "why we call him Lorne," referencing Lorne's disdain for the nickname, given his skin color ("Lorne Greene"), which he first mentioned in Belonging (2001).