This is getting very long and borderline unreadable, so I'm going to split up my replies. It don't know if that makes it easier or harder, but the copy/paste approach is leading to impossible bricks that aren't much good for anything other than blunt force ballistic weapons.
So the first thing I want to reply on are the characters and what we know about them at the time of adventure. On that note, please do do not insult others while getting certain details wrong. It does not lead to anything good.
In BG3, we have Gale that of course could be full of hot air, but he does have that peculiar thing when he dies, and some random hedge-wizard probably wouldn't have that. This lends some credibility to his "master of the weave" chosen of Mystra spiel.
And we have Astarion, who appears to be a wimp that never tasted human blood, but... Look up what a vampire spawn supposedly looks like in D&D. Now look what Astarion looks like. Vampire spawns are arrogant and devious and fairly cunning as far as predators go, but they're not master schemers and they are predators. They are wolves, not sheep dogs. Also look at the rules for vampire spawn characters and contrast with Astarion's stats. Either something is way off or he's holding back a lot.
Then there's Shadow, who looks a bit like some simpleton on a fetch mission, except... She's managed to pick up the super-gismo! She actually got to it and managed to conceal it! That's not simpleton levels of proficiency. Also, you don't generally send useless dimwits on missions to pick up realm-altering super-gismos that rile up all manner of cosmic forces.
Then Karlach or whatever her name is, the girl who may or may not have been a badass, but who managed to just step onto a passing mindflayer ship to catch a ride out of hell and who managed to persuade the not-quite-pally bunch at the trading station to sod off and leave her alone.
Contrast that with what we run into in BG2. Nalia does not have great connections or really any pull in the upper echelons. If you don't help her, she's hiding in the Slums or she gets grabbed by the Roenalls and that's the end of that. She's a member of the elite by class, and she will eventually become a master wizard in the epilogue, but the Nalia that is met by the player is almost out of options. Her land is overrun by trolls, being taken by Roenall, and she's being forced into a marriage with a slaver. That said, her combat skills are immense. She's a wizard with a couple of thief levels in a game where getting a wand of 50 fireball charges is trivial and casting timestop and/or wish-resting is a thing.
Cernd is in prison for his own safety. He's not interested in fighting citizens but he is a druid and therefore true neutral, because that's what druids are in 2E. If people attack him then he would of course defend himself, but if legitimate authority wants to hold him then what grounds would he have to attack them? Therefore he is in the local jail, awaiting a good chance for him to get booted out of the city. He is not on a quest to challenge the archdruid either. He's on a mission to investigate why the animals are going nuts. Once you reach the grove, he can challenge for leadership, or Jaheira can do it, or the player character (if a druid) can do it. The challenge involves a ritual of unarmed combat so yes, Cernd the Shapeshifter would be pretty good at that one thing.
The shadow druid you're killing fairly easily, by the way, is none other than Faldorn, a BG1 companion. And Cernd's personal quest is to find his missing infant child that has been snatched by some evil rich dude who hangs out with a lich. Yes. And what does he do with the child? Why, he sends it off to some grove to be raised well and then rejoins the party and never speaks of it again.
What else, oh yes, Keldorn. Yes, he's technically not in the sewer just to stand guard, he's "investigating" the new cult and where all the people are going. On his own. In a deep, dark sewer, making very little progress. And of course he doesn't know that it's actually a beholder cult. That's not known at all until a bit later in the quest.
