Playing a younger version of Lydia isn't the only thing these two actresses have in common. They're sisters! Havana Blum played Lydia in this episode, and her younger sister Scarlett appeared in Lydia's flashback last season.
The song Alpha and Beta hum in the medical facility is Patsy Cline's "Walking After Midnight."
Visual Effects Supervisor Aaron McLane had a specific inspiration for one of Beta's kills. Beta slowly stabbing a walker through the eye is an homage to Lucio Fulci's horror film Zombie.
Beta doesn't blend in with the herd like the rest of the Whispers because he always wears his telltale black duster. This type of coat is extremely uncommon especially in the heat of Virginia as a duster is typically a coat worn in cooler climates of the northern midwest or on the dusty plains of the southwest.
Gamma is not wearing Enid's clothes.