One thing I don't understand is the video White saw
White saw a video of Non dancing and the other having fun, which is weird since it never happened for us to see, and it would never happened judging on how they're treating Non
The first time they record at the house, they barely torelate him
Phee and White have never been alone together, their only interaction was in episode one when Phee was directing him how to act.
Phee, White, and Tan all wanted to make that movie again and those three always agree with each others suggestion.
Tan and White were alone together in one scene when they found the walkie talkie. Tan was full of praise for White!
I think people are not seeing ghost and it's actually them hallucinating. They are consuming something without them knowing maybe it's in the water. I don't know but it can make sense if we assume the killers all are in the group.
White saw what I assume burnt blister on his skin. Why? Why specificly that? My theory is that White is the brother and he saw Non's body and he was burnt maybe somehow and that's why he saw it
I think White has to be one of the important player in this game and that's why he is Non's brother and not Tan. In some clip you can see Tee and White making it official when Phee and Tan are already in the group.
So in conclusion there are 3 killlers or plotter and it's not only Phee and Tan.