Lilah makes an allusion to Macbeth, where the character Macduff was from his mother's womb "untimely ripped."
The actress who plays Gwen, Files & Records (Stephanie Courtney) also plays Flo, the spokesperson for Progressive Auto Insurance. She has played this role since 2008.
Lilah tells Gwen of files and records, "The boys upstairs are at DEFCON, like 1,000." It is commonly believed that higher DEFCON numbers mean higher threat. Actually, DEFCON 5 (Fade Out) means all is calm, let's go bowling; DEFCON 1 (Cocked Pistol) means we are so screwed.
The meeting between Holtz and Justine calls back that between Merrick and Buffy in Becoming: Part 1 (1998). The only difference is that it bases itself on the vengeance and not on the justice.
Gunn refers to his cousin although we never meet her/him, contradicting his previous remark that his sister was his only family. Though morbid, given Gunn's history, it's possible his cousin is no longer around.