Several advanced(probably) questions

[Mudbill]

I want to add for #3 that it might help to make a custom entity and use the ManPig enemy type (if you have version 1.3 of Amnesia). I've heard this AI seems to be more "intelligent". What exactly this means I haven't tested, but might be worth a try.

As for #5, I think the phonograph automatically becomes stuck by default when you turn it. Maybe try ResetProp("Phonograph");

Lastly, for #6, I have tested moving LiquidAreas before, and if I remember correctly, if you move a LiquidArea away from the player after entering it, the game won't detect the player leaving it, so they'll be splashing around until you re-enter the area and then leave manually. Maybe this is the case with other entities. I can expect moving LiquidAreas with script to be buggy, so worth testing.
If you need the actual water primitive to move, perhaps make an entity out of a basic plane model using the water texture, then set the entity type to MoveObject and have it move along the Y axis.
It is also possible (although difficult) to simulate some swimming mechanics using script. I know there are a few examples here and there on the forums or elsewhere.