These chaps ... were in the Haunted House since day one weren't they? Thats the same head just in a different colour and body.
No, those zombies were added in 2003. The Haunted House had nothing to do with zombies or lasers or any gimmickry of that nature, that was all added later. The prop was bought prefrabricated from TheHorrorDome.com, not designed by an effects contractor like Sparks Group.
In fact Haunted House day one was radically different to how it is now, it's very interesting, you might like to check it out. Have a look here
, for example.
I may be coming across slightly tetchy, but that's just because the idea that 'Keith Sparks designed the zombies' is a bit insensitive: he was seriously ill in 2010 when Shrieksville opened, and died a year later.