I'd like to know this meself as well.
I've nothing against the Larian-designed party NPCs (barely know them at this point), but knowing full custom party is an option would be nice. Even in the original BG1/2, there were plenty of NPCs I couldn't stand or, more commonly, eventually tired of.
Personally, I'd play through enough times to experience each party NPC at least once (though their respective stays in the party are variable lol).
