Or you could just do an open "colour blind" addition and then pick the best woman for the role, yes you may have written her as looking Asian, but that doesn't mean it can't change if she did get cast now would it?
I don't think that's at all in the spirit of a fantasy casting thread. The whole point is to find people who fit the descriptions in the books. We're not subject to the exigencies of real casting here; we don't have to settle for "not quite but the closest we could find."
Well, of course, the real reason this is "fantasy casting" is because there are no plans to put these characters on film, and none of us are Hollywood casting directors. And even if we were real casting directors, we'd be under no obligation whatsoever to pay the slightest bit of attention to the author.
How about Betty White as Trys?