Unicode (3,1,409) 'name' table strings are not limited to ASCII, so you should feel free to use Nüshu (not Nushu) when appropriate. The instances in the name.ID=3 and name.ID=6 strings are for the PostScript name, and should continue to use Nushu. The name.ID=1 and name.ID=4 string can definitely use Nüshu.
I believe to date, we need font family strings to be ASCII. We should have a FB check for that.
However, perhaps we can relax that requirement, so I'm filing this issue to
[x] 1. Confirm we do have a FB check for that (@felipesanches)
An anonymous expert wrote in to the Noto project,
I believe to date, we need font family strings to be ASCII. We should have a FB check for that.
However, perhaps we can relax that requirement, so I'm filing this issue to