While Part 3 saw the deaths of some favorite characters, judging from the list of returning cast it would seem that the dark arts have brought them back to life. Part 4 will feature Kiernan Shipka as Sabrina, Miranda Otto as Zelda, Ross Lynch as Harvey, Lucy Davis as Hilda, and Chance Perdomo as Ambrose.
While this is indeed the final installment of the Sabrina saga, showrunner Roberto Aguirre-Sacasa has said that if there ever were to have been a Part 5, fans might have been blessed with a real Riverdale crossover, but they'll just have to check out the comic book for that instead.