Cannot restore character on locked realm

[Leilleath-moon-guard]

No, it is working as intended. Only when the realms are unlocked and/or character creation is allowed will you be able to restore them.

Locked out of Sulfuras

Unfortunately, it does look like the ability to restore a deleted character if you do not currently have a character on the realm is not possible on Wrath of the Lich King Classic. That is, as far as I’ve been able to find out, currently intended functionality. Sorry.