Ross Lynch (Harvey Kinkle) and Riker Lynch (Trash) are brothers in real life.
The song Lilith is humming to her 'baby' is the song that Rosemary hums to her baby in Rosemary's Baby (1968)
Fred Heads, the band battling Satanic Panic, is the band of Fred Andrews and FP Jones in Riverdale, which takes place in the same dimension as Chilling Adventures of Sabrina.
There are a number of references to the film "Return Of The Living Dead (1985)". During a flashback sequence, Satanic Panic are playing "Partytime" by 45 Grave which was used in the film's soundtrack. Their costumes are also based on the character Suicide, played by Mark Venturini. This episode also features a character named Trash, based on Linnea Quigley's character from the film.
Sean Depner, Sarah Desjardins, and Doralynn Mui also appeared in the fourth season of Riverdale (2017), which is in the same universe as Chilling Adventures of Sabrina.