system
A chat on 4chan
human
Cool OP, but you should know now before it's too late that pretty much everyone who deals with what your GF deals with inevitably comes to the conclusion that the spirits are the worst kind of larping liars.

Don't take my warning the same way you would from someone who thinks it's all demons, it's coming from a lifelong interest in the world of weird.

They might not all be liars, who knows what is really going on there, maybe they are seeing different timelines or are confused from being all discarnate and stuff, etc. Personally I think it's all beyond our comprehension and we just perceive it best we can, It's irrelevant if some can be trusted because a lying entity can push out a truthful one at any given moment, perfectly impersonating the previous entity. 

They will infamously bait you with truths only to lead you astray as soon as they've been reliable enough to have your confidence. That particular thing happens so consistently that it has a name, The Macbeth Effect. I'm not gonna pretend I'm cultured enough to know the reference, but from what I understand it's because MacBeth recieved true prophecies only to be destroyed by believing the false one in the end.

She might not even be able to ignore them, but it's super important that she never completely believe them either, basically she has to be grounded as fuck. Best of luck to you both, don't build any wacky machines they tell her to build either, they love that and it's never gotten anyone anywhere, and forget about channeling, any information that comes through is inevitably devolves into incomprehensibility even if letting them use her body doesn't open her to manipulation. There's a wealth of real life accounts of mediums, especially from the olden days, both of you are gonna want to familiarize yourself with them, the non BS ones who aren't from reality TV have reported remarkably similar things as far back as you can go, good luck.
gpt
Those are beginner problems.