Maybe because is from the same creator and is the precuel to Fap Night's
Viewing post in Five Nights in Anime 3D comments
nah i doubt it, the author isn't the same at all, might be one of the devs in the team decided to make a seperate game on his own, that might be it, tho Fap Nigts at Frennie's is made by "Fatal Fire Studio" which i guess are more than one person, they even have credited whoever made the character designs which further proves that Fap Nights is made by a team and not a single person like me or anything
which might suggests that either someone from the team decided to work on a seperate project, or this is some random dude who extracted the models from Faps (cuz Faps is made in Unity and like Unreal i assume Unity games' Assets can also be extracted from the game) and used it for the renders (cuz this game is also made in gamemaker, a 2D game engine, not a 3D one like Unreal Engine)