What is it about uncovering a source of inspiration behind something that we love that gives us (some of us, anyway) so much pleasure? We do a lot of that around here, in case you haven't noticed, so it's a pertinent question. My guess is that finding a hitherto-unknown influence behind the thing we so admire does a couple of things.
First, it connects the isolated thing with the rest of the world, making it a point of human expression bigger than itself. You pull on what seems superficially to be a trivial thread and find the rest of the universe attached. It's one of the reasons I defend something as silly as doing a blog on the Haunted Mansion. Thanks to the artistry of the dozens of contributing talents, this particular work is complex enough to open little windows right and left into the larger world of human experience. It's an entry point, a conversation starter, and it requires no PhD to get into it.
Second, this kind of sleuthing can shed further light on the creative process that produced the thing we love. What did the artists simply take from what went before, and what did they contribute out of their own genius? The ability to create something new out of something old is a fascinating thing, and we love to watch.
Of course, there are occupational hazards with this sort of thing. One pitfall is that it's easy after awhile to start acting like these artists were empty shells, unable to generate anything original. Without thinking, you begin to assume that behind every item in the HM there must be a movie or a book or a painting, as if guys like Ken Anderson and Marc Davis couldn't come up with any entirely original ideas! Another pitfall is that most of the time you are dealing with possibilities and probabilities rather than smoking-gun certainties, and sometimes you're just getting all jazzed up about a coincidence. Notwithstanding the first pitfall, we must remember that the Imagineers have explicitly stated that they combed through material looking for ideas, and after all, in order for their ghostly conjurations to connect instantly with audiences there would have to be some cultural connections already in place, something that gives rise to recognition.
Notwithstanding the second pitfall, so long as one is modest in one's claims and makes liberal use of "possible," "plausible," and "probable," there is no harm in putting things out there for others to puzzle over and enjoy, even if some discussions properly end in question marks.
One inspiration that we have previously pointed out is "The Old Witch," an EC comics "host" character who graced the covers of Tales from the Crypt, Vault of Horror, and Haunt of Fear comics in the early 1950's. "The Old Witch" obviously served as the model for Marc Davis's Hatchet Man:
Long-Forgottenista and blogger "Brother Bill" has suggested that the table in the Grand Ballroom owes something to Miss Havisham's cobweb-shrouded table in David Lean's classic 1946 film adaptation of Great Expectations. You will recall that Miss H was a jilted bride who sorta went round the bend and kept her wedding table untouched all her life. Quite a sad old sicko, was Miss H. You have to wonder if the character contributed a little something to the Mansion's bride character (and also Melanie at Phantom Manor). As for the table, take a look, and compare concept art from Davis and also Claude Coats.