Theorizing/spitballing here, but what if Project Halcyon *isn't* the demolition of SandSerpent/most of Pantopia East. Before I dive in further, do know that this could be completely wrong, but I am just putting it out there in case it is valuable.
So for starters, we haven't seen the actual permits for Project Halcyon- rather a description of demolition that explicitly mentions "Demolition of existing attractions, foundations, fences, trees, and site clearing." Remember that all this is still technically the case in Jungala, just with SBNO attractions of Jungle Flyers and the (burnt) Wild Surge. One note within the permit's response to the city involved specific, protected trees- a lot more trees are located in the Jungala area, which is literally called the "Treetop Trails" due to their integration into the area. The description of the permit for Project Halcyon also expressing mentions 4 affected buildings. While this could mean those four attractions in particular, this does leave some questions, like the Falcon's Fury MCC room kinda in the middle of all that. Does Jungala potentially actually include four buildings? Also, after a quick search, I couldn't find any permits from when Phoenix was demolished- which makes me wonder, could this also be true for the other attractions in that area?
Also, it seems to me to be a bit of a stretch to demolish that whole section of Pantopia, and open an "exciting new addition" in Spring 2024. There is, however, already started some kind of work backstage to Jungala, as I have seen some walls around this general area:
Now obviously that's not going to be the layout of a ride, but it seems like a logical base as to where work could occur in Jungala for the start of a new ride. Also, gut feeling tells me a family ride makes a tad more sense in the Jungala space than in the middle of Pantopia, which could in theory be used as the epicenter of future expansion to the park.
Just figured I'd throw my two cents in, and obviously take nothing as confirmed. But those reasons are why I think Jungala, rather than Pantopia, might be responsible for Project Halycon as we have seen thus far. I could be completely wrong in this, but I figured I'd put it out there as a possibility, even if albeit a slim one.
