I assume what OP really wants is a customizable party...and *not* origin characters who have, well, a premade origin which is tightly coupled to their class and identity (Gale being the most obvious case). If you're going to simply throw that away, then you don't want to play an origin character - you want a character who's story you write *completely*. Incidentally, I don't recall past BG games allowing you to simply throw away the starting class of any NPC that joined - you could dual/multiclass later, but that base class was their prior experience.
