By the way, in Russian, there’s a similar glottal stop situation with the old character Yer or Hard Sign, ъ, often replaced by an apostrophe in modern Russian. No other language using Cyrillic alphabet has this character except Bulgarian, where it denotes a specific sound. For Russian IDNs, should the spelling with no Yer be a variant of the spelling with it, and vice versa? There are a number of other characters in Russian that are somehow “special”, including the mentioned Ё or characters that in some fonts may be confusingly similar to other letters. In some cases, it is not reasonable to treat these similarities as variants; instead, the confusion can be avoided prohibiting registration of names that can be confusingly similar to a canonical string that has already been registered.
Perhaps, Vladimir Shadrunov from the .tel Registry could share Telnic’s experiences in defining language policies for Russian and other supported IDN languages in .tel.