[Tony]

Yeah. It's simply for the fact that Halloween 4,5, and 6 do not exist in the continuity featuring H20.

You could pretend that perhaps John was born after Laurie faked her death and make it work. I know Jamie has a pic of her mother in Halloween 4 and act as if she misses her a lot. But perhaps Laurie faked her death when Jamie was 2 or 3. Perhaps Jamie just says she misses her when in fact she doesn't even remember anything about her. Just a mother/child instinct or something. The pic that Jamie has is obviously a very old photo.

Just one way of making it work.

You could also throw in the fact that Laurie is so overly protective of John because she's kept up with what all went on back in Haddonfield over the years. She knows that her dauther didn't make it and she doesn't want the same thing to happen to her son.