I wonder if the game locks out the origin characters, but not the party.

As in, maybe we still have to pick select origin companions and the rest disappear, die, turn against us, whatever.

But the party isn't technically locked because we can still mix in the non-origin companions: Halsin, Minsc, Jaheira, and Minthara.

*

I really hope we can still get Minthara if we don't turn against the tieflings.