The name of Mrs. Blankenship is a reference to Halloween III: Season of the Witch, in which Ellie says her father had an appointment with Minnie Blankenship.
In the original draft of the movie, when John came home from work, he turned on the TV and the scene of the boy dying from the mask in Halloween III: Season of the Witch was shown.
Although the infamous Producer's Cut of the film was never officially released, bootleg versions were made available a few months after the film's release.
The original conception of the "Thorn" cult apparently was much more in the vein of Roman Polanski's vision of the Satanists in Rosemary's Baby, more mundane and real-life, as opposed to what Daniel Farrands has called "the Temple of Doom version" in the final film, with underground lairs, altars, and robes and hoods.
When Michael was chasing Tommy, Kara, Danny and baby Stephen down the hallway, Michael was played by A. Michael Lerner. The Smith's Grove Doctor running from Michael also was A. Michael Lerner's real life father.
As a result of Donald Pleasence's death, as well as creative differences between Joe Chappelle and the producer, and an allegedly bad test screening of the original work (the famous producer's cut) re-shoots were done as well as lots of editing, to the anger of most of the cast and crew. Many vowed never to make another Halloween movie again after all the changes.
The producers of the movie wanted Brian Andrews to reprise his role as Tommy Doyle from the original Halloween. However, Andrews did not have an agent, so they could not get in contact with him. He regrets missing the opportunity.
According to Marianne Hagan, she almost did not receive the leading role of Kara Strode - Miramax Films purportedly did not like her physical appearance, deeming her "too thin", and her chin "too pointy".
Daniel Farrands stated in an interview that Joe Chappelle used little to no ideas from his script. He had completely re-written the entire third act which included a completely (albeit confusing) different ending. Daniel's original script dealt more with the cult and rune of Thorn.
Most of the cast and crew disowned this movie. On the 25 years of Terror DVD, they stated that the studio, producers, and director interfered and argued to the point of ridiculousness which resulted in a very poorly directed and edited film.
Daniel Farrands' original script was far more moody and psychological than the final draft. After reading the script, one of the execs at Dimension films could not sleep that night and therefore called Farrands immediately and told him that they wanted go forward with it. 'Donald Pleseance' himself supported the original script and immediately signed on to make the film only to find out that the script was being rewritten.
The original title of the movie was "Halloween 666: The Curse Of Michael Myers". There are even existing ad prints and early trailers with that title. Later, it became "Halloween 6" and finally "Halloween: The Curse of Michael Myers".