In the bizarro world that is contemporary American politics, anything is possible, as we learned to our horror last year. But, generally speaking, none of the people you mentioned (again, with the possible exception of Biden) are perceived as being in sync with the mainstream of U.S. voters, nor do any of them have major name recognition. Of course, there's a long time until the election and things can change. And, historically, candidates do tend to move more to the center once they become the party's nominee. So, we'll see.