Yeah, and surprinsigly, Spanish dismisses this Latin root and uses two words: The first one, ternero from the other Latin word tener ("tender", "soft", "delicate" and ultimately, "young") and the second one, becerro, most possibly from Basque origin (ibicirru?).
You are right. If vitellus had been preserved in Spanish, it would have been vidillo or vedillo.
That constructed word (not actual Spanish), vedillo, makes me think of Catalan vedella, which means calf. Interesting :).
Yes, or "carne de viţel" as ID-07 said. "Viţel" also works alone and one can tell by the context if you are referring to the meat rather than the animal. Depends on how specific you want to be.