Gosh Darn Monsters [spoilers]

[Airyll]

Alrighty then! So this is kind of a question thread, based on my own experiences, trends I notice within the game aaaaand watching people play through this ingenious and utterly terrifying piece of work. If this has already been answered somewhere, I do apologise in advance; I searched around and didn't exactly see the answers in the numerous threads I checked.

Onto the questions!

1. The monster in the archives, that beautiful pianist he is, never actually seems to do much aside from moan at you. If you're lucky enough to see him he wanders off down the corridor you have to leave through (which honestly panicked me quite a bit) but he's not actually there.

Spoiler below!

You can walk through the entire level seven times over after this and he never shows up again. Not visibly, anyway.
Is this guy a hallucination or what? Or do I just scare him more than he scares me?

2. The same thing for the monster in the wine cellar. He's there, and he's a bit more obvious than his counterpart in the archives because he happened to drive me batcrap insane and wouldn't leave for several minutes; I was tempted to just run into him and end it all because it wasn't like my sanity could drop any lower.

Spoiler below!

Once he's out of sight though, he too seems to be gone from the entire level. Hallucination? Does he ever appear again, patrolling? I don't actually know if this monster will attack you if you continue to stare at him and draw his attention, and I'm not exactly willing to test it out either.

3. Similar to the above two scenarios, but this is more about the spawning behaviour of monsters. Now all monsters after the entrance hall do actually seem to be capable of killing you and some seem more vigilant than others, but they all seem to share some behaviour regardless of who is playing the game or where exactly you are. Discounting the water monster, of course.

Spoiler below!

Monsters seem to spawn loudly. Like you can honestly hear them from a mile away and run and hide long before they see you. I also notice that if you wait until the music fades or don't follow the monster they seem to... disappear entirely. In fact you can even follow them, provided you let them get ahead and turn a corner, and they still just seem to vanish.

Are they programmed to despawn if they don't find you, or are they superhumanly fast and have the ability to ghost through walls? Because either explanation would explain why so many monsters seem to be haunting the corridors of places like the prison, but also vanish completely from your path if you hide from them and let them pass.

4. A final curious question. I heard that you can

Spoiler below!

glitch the servants by standing atop of tables or barrels, at which point the brutes seem to be full of infinite stupidity and just can't reach you. Now while I didn't play the game this way and don't really care to (because they themselves scare me and being trapped in a room with one would still have me crap enough bricks to build a house, safe or not) I did wonder if this was in any way related to the programming of the water monster?
After all, it makes sense to me given the fact that the water monster is programmed to be equally incapable if you are on raised ground.

Thank you in advance for any answers. =3 I'm really enjoying this game at the moment; it's one of the few games I can label a true horror and it's an absolute gem of a game in that it's the only one of it's kind that scares me so badly... I keep coming back to play further into the game and get scared more.