I'd agree that Wyll is a hair's breadth from committing a crime against humanity. Or rather, goblinity. Is that a thing? His heroics are just a positive spin he puts on his hatred for gobs or a part of a pattern of self-aggrandizement.
I generally like Gale, but I think that deep down he's selfish and narcissistic. He doggedly pursues things that give him power or preserve his life. If he were truly selfless, he'd realize that delaying the curse is pointless. He should just row a boat out into the ocean or go into the desert and self-destruct with the fewest casualties.
Lae'Zel is very lawful, as you say. But whether he mistreatment of others is the result of indoctrination or not, it's still mistreatment. I'd say she's evil with a minor capacity for neutrality, as she can at least see some pragmatic value in letting some people or creatures remain alive. She is a character with a possibility for dynamic character growth.
I really think Shadowheart is not who she says or even thinks she is. She believes and wants everyone else to believe that she is lawful evil. But she repeatedly appreciates the PC's positive actions and has some conflicted feelings about Selune. Since Shar is all about secrets, I suspect that Shadowheart's true identity is a secret that is being kept even from herself. Sort of a reverse Darth Revan scenario.
Asterion makes it fairly clear what he is. He's venal, selfish, hedonistic, and bent on revenge. Neutral Evil is the correct call.
I find it funny that the "Good" Origin character is the one who has spent a lifetime spilling blood in Hell. But what little we know of Karlach, she seems alright. She probably has some real emotional baggage though. It's hard to imagine going through all that and not harboring some festering trauma.
