It seems to me that there is backward causation under the decoherence interpretation, as the world we inhabit is affected by the experimental set-up (there's either a diffraction pattern on the back screen characteristic of a wave, or a pattern characteristic of a single slit). I really think people tend to overestimate the latitude that exists among the various quantum interpretations. They are just interpretations, after all.

I don't think that Omega knowing a person better than they know themselves is sufficient to explain the 100% accuracy of Omega's prediction.