Well I tried to reach out for the answer about transfers when Blizz announced last chance of transfer from SoM1 13 days ago
However outside of US forum barely any answers are given and usually they are in no-reply form.
We don’t know if free character (ghost) transfer destination would be there all of Era realms, some selected ones or if Blizzard allow to transfer fallen HC characters to Wrath Classic (and Cata Classic, if that is to come) progression realms.