Revealing mistake: When one of the sailors peers out of the circular window and sees the fog bank you can see the window has not been lined up properly with the superimposed fog as the two collide at the right edge. The film then cuts away to the sailors and then back to the window again and this error has been fixed. (00:16:30)
Revealing mistake: When Nick stops his car and turns it around and goes down a different road (after the fog update from the lighthouse over the radio) you can see the large light attached to his car's dashboard used to illuminate it. (00:56:37)
Revealing mistake: The door to the weather observatory shows that it is a set by the lack of a complete door frame at the bottom which would let rain and other elements in under it.
Chosen answer: From what I've gathered from listening to the DVD commentary there is no connection between the six that must die and the original conspirators (Father Malone aside). I've always found it quite silly that fog, which is seen roaring down the streets of town, seems hell bent on getting the main charaters and not bothering anybody else in the town.
If one reads the novelization of the film, it's revealed that the six were descendants of the original six conspirators. Although it wouldn't apply to the movie, it's an interesting plot point.
dewinela