re: Of these three pop singers, which do you think is the most talented?

I'd go with Gaga in terms of talent. I know she plays piano well which in turn gives her a firm understanding of not only how to perform but how to compose, even if it's on a shallow level.

A singers voice is totally interpretive to the person listening. Granted, some are better than others, but musicianship is (playing, composing music) not really subject to interpretation.

You can either play the gig are you can't.