Translating the Worldwide Phenomenon

In January, the Guardian ran a story on the special challenges of translating the Harry Potter books. It asks:

When Uncle Vernon hums "Tiptoe Through the Tulips", do you let him keep his Anglophone song and just translate the title? Harry's Spanish uncle hums "De puntillas entre los tulipanes". Or do you find a local equivalent, like Germany's Onkel Vernon, who goes for the rather more German folk hum, "Bi-Ba-Butzemann"?

Spanish readers will find most names and invented words unchanged ("¿Hagrid, qué es el quidditch?"), or translated literally. So the Spanish is faithful in one obvious sense - but while the names may be unchanged, does the name Quirrell really sound as nervous, stammery, querulous in Spanish? Does Hufflepuff sound as ineffectual, dumb and huggable as it does to English ears?

And then there are the clues J. K. Rowling embeds in her English words, such as:

Tom Marvolo Riddle may be an anagram of "I am Lord Voldemort"; but it's not an anagram of "Je suis Voldemort", so in France he's Tom Elvis Jedusor.

No wonder he wants to be king.

Not discussed in this European article is how the wizards' spells are Latin. How do they get translated for cultures that don't descend from the Romans the way that Europe's largely do? And within Harry Potter's reality, do wizards in China or Kenya or Kuwait use the same spells that he does? [Gili, any answers?]