Some flaws...

[Kedjane]

In the part in the kennels where you die in the darkness - when you turn on your flashlight and look around before you die, you can see that there's absolutely nothing there, though I'll assume it's supposed to be Frisk the dog man.

I've heard this once before, what area is this you're talking about?
If it's the place where you have to push crates in front of holes it's obviously rock worms that kill you and not Frisk. Or do you mean some other place?
Also the Amabel thing has been discussed several times. We don't know at all what happened in there, or even if Amabel was under Tuurngait influence. On the death thing, shortly: if you believe it can kill you, it can kill you. Clarence is able to manipulate your mind into killing youself, but only if you believe in it. A sick persons mind can kill the person if it believes it is dying because of some disease or mental disorder.