This is a really good idea <3.
It would add so much to the lore, and it should be harder to persuade the companions to join you too imo(still persuadable, but just make you need to persuade them instead of them accepting your leadership so easily like it is for a High Elf or Human).
At least with the present companions, it wouldn't make much sense.
Lae'zel doesn't like everyone except Githyanki
Shadowheart has nothing against the Drows (but she hates Githyanki).
Astarion is Astarion
Wyll hasn't reason not to join us at the moment we saved the people at the gate.
Maybe Gale might have a problem, although he's desperate enough not to be picky about his allies.
