I could really hear Misha's voice in the dialoue you wrote-it was that true to character.
And I'd like to think that Cas was giving this report to His Father by way of prayerful contemplation as he sought to figure out the new way he must procede to carry out His will.
This was excellent. It captures pretty believably what is probably going through Castiel's mind right now, insofar as we can fathom it. I also thought the idea of the vessel as a devout pagan was a nice touch.