Gale- "Good" he stops his fanatic devotion and power hunger. "Bad" he will be consumed by it and will just end as sociopath or will blow off some city.
Wyll- Seems like Larian favourite character archetype- Monster Hunter contracted with the Devil. Jahan was cool, so they should handle it. Good" I guess cutting the deal with his Devil or somehow making it mutual relationship (I just have feeling that she is more like Luficer from DC rather than just pure Evil)? I mean it's hard to say until we will see what kind of Devil she is. "Evil" something like him becoming the Devil, so thing he hated at the start.
Shadowheart- will say it again, probably the most interesting character right now for me. Pretty much Selune blessed child, but raised by Shar cult. "Good" prettych much some kind of hero path (from neutral opportunist) and things like dialogues after saving Tieflings vs dialogues after Goblin win confirm it. "Evil" will end up as Shar enforcer.
Lae'zel- prettych much straightforward character which is nice. "Good" ends up as some kind of Githyanki rebel. "Evil" just stays as she is at the start and will have higher role in her society.
Astarion- free spirit guy, so probably most open for endings now. "Good" he becomes a Vampire Hunter? (Vampire Vampire-Hunter) "Evil" something like killing his master, taking his role and enslaving as many people as possible.