Hello, this will be my first blog ever on this wiki. So let's start out with my very first theory.
Ok, so do you know how in the Five Nights at Treasure Island trailer and the 'welcome to the family' teaser that white creature has her hand on oswald's head? It could by possible that back when Treasure Island was open and NOT abandoned, this creature was actually a real person who possibly visited the island for a vacation and at that time could've liked Oswald alot. However, on the way there she fell out of the boat that could've been taking her to island and landed into the water (which was filled with parasites as mentioned in one of the TGsEE logs). She drowned and died in the process and when the Resort closed at night her corpse landed on the shore and her ghost took form and transformed into this unknown white figure (which could possibly mean why her entire body is white because she's a ghost).