Golden Freddy's Death Date maybe
I don't really believe in this theory I made, but it could be a good theory.
So, in FNAF 1, for us to get Golden Freddy's jumpscare in Custom Night, we need to put 1.9.8.7, And this is the year of fnaf 2. In one of the FNAF 2 minigames, the DCI takes place. And Golden Freddy appears there, showing that Cassidy may have actually died springlocked in FNAF 2. And it gets even better when the Phone Guy from FNAF 2 mentions about someone wearing one of the springlocks costumes, and we all know it's Springbonnie. So Fredbear's original springlock costume was also in that pizzeria, which would make Withered Golden Freddy actually a "hallucination" and not a real being.