But when Walt passed away and the project got back into development, there were some conflicts among the team as to what it should be. Should it be scary? Should it be funny? And in the end, it was sort of resolved by splitting up the work in one sense.
and that it was originally envisioned to be a walk-through:
The Haunted Mansion was originally going to be a walk-through experience, with a cast member, a butler or a maid, taking small groups of people from one vignette to the next as the ethereal moment unfolded. And even Walt realized at the time that, that was going to be problematic from a capacity standpoint. You just couldn’t get enough people through the Haunted Mansion.
I'm glad they thought through the whole thing before deciding.