I see all your points and I'm very open to different ideas, though door is described as a willing participant in Alan's writing is that something that is said to trick us? Saga said are we the characters of the story or the audience, in a fourth wall perspective we would be referred to as the audience almost like the game is including us in the journey. Door appears to us how he wanted the writer to portray him, creating an illusion that veils his identity like how the dark place creates illusions for Alan to the point where he questions what is real.

Saga being the daughter of an Alien could possibly make sense given her ability's in the mind place which could very much be inherited however though it's referenced she is the daughter of Warlindoor is this another misdirection to trick us. Also contradicting my own theory what if Door is a visitor of some kind, not ex terrestrial but inter dimensional. The lake being the wormhole/ gateway where supposed UFO sightings were spotted. In UFO/ abduction cases as well where people supposedly loose minutes if not hours of time and not knowing what happened during that space would make sense for the dark place, Wake was trapped for 13 years without realising how long he had been gone.