I think if people know about Mind-Flayers, they know about their ancestral enemies who exist in the Aether. It probably isn't common knowledge, but it isn't going to be completely unknown. There's is supposedly a starjammer port at Waterdeep, though they're not supposed to fly in. I personally find that pretty contrived, but so is a lot of the FR.
Thanks for the response. That would give us some flexibility in what we would expect specific characters would know, and thus some roleplay flexibility.
Since Anska brought up how Gale's conversation about his family name is newly fixed, I would like to say how happy I am about that fix. It makes Gale's scene reclaiming his name more meaningful, since it now has the proper buildup explaining why he had stopped using it.
... It's an ending scene, my comment isn't completely off topic
