Many of you have probably seen the above video (or others like it) from this years D23 and here's my crackpot theory.
Let us assume that Guillermo Del Toro is still going forward with his proposed Haunted Mansion film and that he's still planning on making the Hatbox Ghost a featured character. Could this AA be based on possible concept art from the film and (possibly) be on his way to be installed in the Mansion?
It's obvious that this rendering of Hatty looks quite a bit different than the 1960's original and they've obviously gone through a lot of time, trouble and expense in designing/creating him but I don't see any way that this particular AA could execute the famous "Head Trick". If this AA couldn't perform the gag, perhaps another one is being designed that could perform the feat and both designs are being considered for the attraction.
Now, let us assume that IF the film is made and IF it's successful, and IF Disney decides to add Hatty to the Mansion, that they may install 2 or 3 HBG's to the attraction much in the same way as the "Phantom" in Phantom Manor in DLP or (dare I say) like Jack Sparrow in POTC. I could see them adding two HBG's in key scenes like the ballroom or the endless hallway and then have a third somewhere near the end where he performs his disappearing head trick. Of course, the original changing light effect didn't work so they would probably make this figure as a projection like Constance in the attic.
Now, before I'm viciously attacked for proposing this, I want to add that I'm not advocating this idea at all and it's merely the product of my warped mind and that if Hatty is ever installed in the Mansion, I would hope that they would take the greatest care and consideration before doing so. I'm merely suggesting a scenario that Disney MIGHT take based partially on what happened to POTC.