Well its very clear they're branding it as the return of the HH in some manner, so why remove those very elements on what made it the Haunted House? That's like Pirate Adventure Being rethemed to a carbon copy of Disneylands original Pirates of the Caribbean, with only the branding actually being relevant to Pirate Adventure as fans remember it as. Yes, they're both themed to the same genre, but they're both totally different experience as well with false advertising. Yeah, one is better than the other, but it isn't Pirate Adventure anymore, it's a completely different ride for the sake of it. Piraten of Batavias was valid as those original scenes no longer existed after the fire, while on Duel, many bits of the Haunted House does still to this day in pretty decent condition. So again, why remove them when this overhaul is obviously Haunted House related?
If they were retheming it to a completely different attraction, the removal of the HH scenes would be valid as it wouldn't fit in with the new theme. But I this case, that obviously isn't happening with evidence from John Burtons Social Media, and the teasers around the facade of the Building. If they're going to bring back the Haunted House in some way, why remove the Haunted House scenes at the same time with something completely different for the sake of it while pointlessly spending more money? Then it wouldn't be THE Haunted House anymore, it'll be just A Haunted House.
I agree with
@Benjsh here, I imagine most of the budget is going to be put into refurbishing the ride system, refitting the ride vehicles hardware, which are incredibly expensive already, and the couple of new scenes. Apart from that, all I can see is some spruce up and major TLC in the surviving scenes, along with new or old sound effects fitted in, and different music.