I doubt there's a world where Universal would drop the "Halloween III" from the title even if they wanted to, for several reasons. Intellectual property licenses tend to be very specific in how franchises and characters are portrayed, and there would likely be a stipulation requiring that the full title must be used. I'm sure Universal would have loved to drop the "4" in Halloween 4 - who cares about Halloween 4 outside of franchise diehards? - but keeping that number distinguishes it from the original Halloween and its remakes/new sequels, which Universal cannot use or associate themselves with.
Furthermore, we forget there's another 70s cult movie called Season of the Witch... so simply calling the maze "Season of the Witch" would likely create other concerns beyond guest confusion.
It's all a moot point, I think, because I suspect you are right: Orlando will follow Hollywood's lead and create a pseudo-original story set in the world of Halloween III that happens to feature Michael Myers, who will be included with the license. This is a total guess, but the plot could involve the coven's activity opening a portal in which The Shape emerges to wreak havoc on what remains after the Silver Shamrock massacre. They will likely be limited to environments and character specifically associated with Halloween III (meaning probably no Loomis or Laurie).
Orlando has a track record of creating these pseudo-original workarounds that let them play with franchise toolboxes: Alien vs. Predator and Freddy vs. Jason both mostly ignored their underlying films and instead used their characters and environments to make something new.