You have all these narratives where no one at all has a name, or has something like Snow-White-Fire-Red, or there is only one name -- possibly shared by two or three characters. (The Russian "Tale of Three Ivans" does not name a single other character than those three.)
And you still want the characters to have distinct names. Even raiding related legends does not defeat the issue that the names frequently repeat from tale to tale. I have not run across a Tale of Three Jacks, but that doesn't mean I can raid three tales that name the hero Jack. Or even two that call him Siegfried.
At least a polyglot fairy tale land lets them be Hans and Jean and Ivan and Jack. . .