I'm not sure what your first question means.
Maybe you think that "ĉu" means "what"? It does not; it's just a particle to make yes-no or choice questions.
So "Vi trinkas teon aŭ kafon?" is not enough - it has to be "Ĉu vi trinkas teon aŭ kafon?" for "Do you drink tea or coffee?" / "Are you drinking tea or coffee?"
And that can be either a yes-no question ("Is it true that you are drinking either tea or coffee?") or a choice question ("Are you drinking tea? Or are you drinking coffee? Please tell me which of the two it is.").