>>212772379For a childrens book I feel the silly translation were mandatory to get a french kid to feel the same way an english kid might reading the names. A french kid would have no reference to what "Fawkes" would have meant, but with Fumseck the emotion would be roughly the same, even if you're missing the mature reference (from "fumer"/smoking, "sec"/dry, "sec" also evoking the action of doing something a lot in slang).
Same from Hogwarts becoming "Poudlard" (roughly Licelard), not the same but with a similar effect on a kids mind.