The release trailer is out and I have a few theories:

Chica Eating:

In the second clip Chica is shown to walk o an area and the eat something (Picture One). I don't know why she is eating or if it is the soul needing food (Walten Files Style).

Sun Rise and Moon Drop

After the Chica clips there is Sun Rise saying about how he warned him when the lights when of and started to panick, turning him into Moon Drop (Pictures 2 and 3). I believe that Sun Rise is a helper in the Early game, but becomes Moon Drop later. (Also this is my favourite scene)

Glitchrock Freddy

In the scene showcasing all the animotronics. Glamrock Freddy's eyelids can be seen twitching, followed by him falling over (Pictures 4 and 5). So Freddy is glitched in some way, which is why he doesn't attack gregory but insead help him.

Those are all te Theories I have for no, but remember 12/16/21.