Putting aside the question of the legal requirements (which can necessarily only approximate the ethical requirements), isn't it reasonable to just say that he should be hired if and only if the hiring committee thinks his beliefs will not unacceptably interfere with his job (including, for instance, the possibility that he is a "fraud")? Dawkins trots out all these extreme cases where we would be very worried in order about job performance to argue that religious beliefs should be fair game, but doesn't convince me at all that "if a young earth creationist is 'breathtakingly above the other candidates', then the other candidates must be so bad that we should re-advertise and start afresh." Rather, it just advertises a naivete about how flawed we humans are. If we rejected every candidate who has some self-contradictory beliefs because we take it "as a revealing indicator that there is something wrong with his head", we wouldn't be able to fill any jobs. Anyone who thinks they have reached some sort of platonic ideal of rationality---and that those who haven't should be ignored---is deluding themself, whether or not they may be more consistent.