Long reply but... Orion kind of has an issue as a character... or not?
First, you can only guess Liz met Orion on some online chat group. The notepad diary makes it sound like Liz only knew Orion for 2 months, where Orion introduces her to OtherWorld and also Scott, before Liz did the ritual with Orion on Halloween.
When you first talk to Orion though, he talks to you like he's still alive and presumably in his 30s, so he says in your new chat that "you used to be friends as kids" when you say you can't remember who he is.
That's when he tests your knowledge of the ritual you did and then gives you a new invite to OtherWorld. Once you're in though, he types like he really thought you were Liz.
Also I think the webcam footage would make more sense if it's a new owner (like you, RIP) who recently died from cursed PC stuff, and Orion's soul simply still has PC access unlike Liz who only has OtherWorld access. This would make sense since Orion never had that cursed text font like Liz did and can use the chat app like normal. The reason I don't think the body can be the real Orion is they did the ritual 20ish+ years ago, so his body would've been cleaned/just bones and building abandoned/cleaned/resold/destroyed by then). This could just be dev oversight in the story though. Or maybe the story takes place only a few years after the ritual but I missed a clue somewhere.
But again, Orion types in the chat app like he's a regular human and not someone who's also ritualistically digitalized himself. He's obviously in OtherWorld and can talk to Liz, yet he gives another code to Liz on the chat app acting like it is her and he believes her and hasn't talked to hear in 30 years?
I'm just gonna say Orion's lost his memories like a schizophrenic (due to soul degradation and the ritual) so he forgets Liz is in the game and fools himself to believe he's a real 30 year old that can use his PC still (since he still is). Seeing Liz pop up as online on the chat app must have made him immediately log out of Otherworld and even forget he probably just saw the real Liz there.