I mean, they absolutely get the kid event right, and HoS has long had a "#2 but they try harder vibe," so potentially a market. If anything, turn Orlando into even more of an October mecca for Halloween junkies.
Ton of room off to the right of the entrance, some of it indoors even (convention/classroom space). Not sure where you could spread out with other houses, tho. Especially if you want to keep the scary stuff removed from the main trick-or-treat path during the daytime and keep guests far away from animal enclosures at night.
Two biggest issues I see: staffing the houses (can't be that many make-up people and scare-actors in town). And the initial capital outlay to design, build and market this the first year. A corporate sugar daddy like Comcast could front that, but the parks don't have that anymore.