I hope they do not use copypaste dialogues like in IWD or NWN2, where they refer at Duergar, drow, svirfneblin or races outside the Human reings as "Underdark dweller" instead of a different dialogue for every race... =p
I mean, Githyankis would have little in common with the underdark races in... uh,... everything besides despising mindflayers, I think.
I agree, giving the unusual race options is pretty hollow (feels tacked on, even) if in dialogue it makes no mention of it. This is why I think those races should just be avoided.
On Drow, however, they're not as taboo as they once were. They can safely and actively trade in the city of Baldur's Gate for example.