Thanks for the interesting post.
I'm curious about where you see prophets consulting with kings. It is more common to see the biblical prophets as as addressing the people as a whole, along with priests, other prophets, elders, etc., and not serving as monarchical advisors in the way that prophets in the surrounding cultures did. I'd be interested to know which passages you are thinking of.
I'm also curious about how you think Obadiah fits the description you give. If Obadiah is a rant against Edom, in what way could Edom be understood as bound to Mosaic law? That is, what's the connection you are drawing between your thesis and your example?