As to favors. The Bible says God is a jealous God. It does not deny the existence of other powers in the world, it says that God will be wrathful if you worship them.In 'Supernatural' you have God, the angels, the fallen angels, the angels who have fallen into hell, the demons, and then a whole slew of non-Judeo/Christian monsters/powers. If the trickster for instance does not fall into one of those J/D categories, then perhaps the favor comes from him or some other power like him that exists outside of Judeo-Christian recognition.