I just finished my first viewing of the show. I'm trying to figure out why the behavior and appearance of the ghosts are so vastly different at times -- sometimes appearing benevolent and sometimes scaring the hell out of their family -- and the only thing I can think is that either:

A) There's a genuine spirit of the person and a separate "imposter" version that is an illusion created by the house to torment the family.

B) Both versions are the genuine spirit of the person, but at different times following their death. So they're ghoulish and terrifying while they're hopping through time "learning all the secrets" and coping with their own deaths -- mentally scattered in a similar way to when Liv was losing her mind. Then once they've gotten a grasp of how the afterlife works and have accepted their death, they're able to present to the family as their helpful, peaceful, "normal" selves. We just see it go back and forth between the two versions because they're displaced in our perception of time throughout the process (like when we see Nell travel back to her critical life moments.)

In the final episode, Nell makes a comment about how time isn't linear and that it occurs around us randomly like rain/confetti. She also mentions that things used to be really confusing and out of order for her. So I'm kinda leaning toward Option B.

Does this make sense or am I overthinking this? Haha.