I'm not sure what you're aiming at with that. Some snakes' tails rattle, and others' don't. "A snake's tail" is not a synonym for "rattle," because they're not the same thing, even if one sometimes includes the other.
If the only baby's toy ever invented were the rattle, then "a baby's toy" would be synonymous with "rattle," and therefore illegal. But of course there are countless other toys besides rattles, and some of them, whether by design or defect, make that noise nonetheless.
Vanna is, in fact, white. I don't see how whether her name was intended to reflect that fact or not has any bearing on the clue's legality.
(This whole thing reminds me of a 1988 Family Feud episode. Pointing out a coincidence, Ray said something like "we have the Brown family against the White family, and they're color coordinated.")