I think that the Theocracies will come around. There are only the Iashalurians who are throwing a fit about it right now. I attribute that to Aram opposing anything Allisons says. As for preaching to nobles, nothing stops us from doing that. There is no game mechanic to preach to a noble. You just need to convince them to join your church.
It has been explained often that the laws and core ideas of the church are the core ideas of a theocrecy. You would think that they woul not need to come around. As to preaching to nobles it boils down if the realm will allow it. I am guessing that a forign priest can be arrested (from a mecanic) for just abouythingr. The questin is how much political trouble it causes on both ends.