Hourglass was originally going to jumpscare the player, but it was scrapped due to RAM problems said by the Game creator.
But in the MFA of the game, Hourglass's AI section was titled "Hourglass was never planned" there is also an unused screech for him:
A quote for Acephalous was originally going to be in Five Nights at Treasure Island by Matthew (AnArt1996), the quote being: "Give me salvation"
In the end, the quote was never found as an edited version, and was found by the user Jacksonfnaffan. Within the Sound files, the quote remained unedited. The original file in which contained the unused quote can be found here
Another content that includes Acephalous was when he would enter the Staff Area, then would enter Character Prep 1, and seen with Disembodied in his hands. He would then be seen running through the Staff Area while wearing Disembodied as a head.
In AnArt's version, Matthew may of changed Ace's AI to be a Foxy based character from Five Nights at Freddy's but this remains Unknown due to AnArt cancelling his versions.