
Just wagering a wild guess here. Looking on Google Earth you can now see a boundary separating the new development going in where there used to be woods. The original house location has been sadly filled in and submerged in water. The opposite side shows a swath of land that existed but was vacant throughout the original run on 10 and 9. Older imagery shows cars parked here during the original runs.
Aside from the new house being built actually inside the park and risking noise from the park and rides, I'm thinking this could be the new location. If they plant some trees and put up a fence on the side of the road, this could make for the perfect spot. Even the two red trailers are still there from when the original house was still being used. Can't help but wonder if Dreamworld has access to this location still. However, it could be odd to put it so close to a public road.
I find it unlikely the amphitheatre will be re-built, especially since a new ride is being planned there. I would assume they're using the other theatre in the park, so this could be moot as it would be a significant distance.