So sorry for the late reply!!! Thank you so much!!! :D Unfortunately there's no formal guide lol... however, I can put some in spoilers below, but I'm honestly going off memory LOL:
If you let both the Nurse and Monty through, you'll get an ending.
If you let any malicious entity through, you'll get an ending.
Depending on how you kill Fairy at the end, you'll get an ending and one of a few variations.
Sorry this is so scuffed... they really are all from memory lol... there's might be a few more ways I don't even remember... thank you so much again though!!!