Sacred Haven of Debauchery

By the way, has anyone not killed Drizzt during a playthrough of BG1-2?

I didn't kill him in the first one. It was my first playthrough, and why would I engage in such a grind that wasn't really intended by the developers? Maybe I'll knock him off next time I replay it.

Restrictions on "good alignment," if I remember correctly?

No, he just has worse stuff than I do. The only thing is that Drizzt had a good saber, defender +5. The others aren't very good. I don't need them for anyone.
If you remember who's who, you can see from the portraits that I have at least three good characters in my team.

(although he seems to still be wandering around that location)

That's unlikely; he left after the conversation, for example. Maybe they only left him in the trilogy for the sake of convenience.

Yes, he seems to be quite good at taking down vampires; you can just stand on the sidelines and occasionally heal him.

Or you can watch them fly to pieces, struck down by the priest's banishment, lol