I agree that it can be confusing, as there's a lot to keep track of. I think things will be easier once we see more of the Radiants in action. To me it's most confusing because the words are so broad and Sanderson doesn't explain them much.
I think that while the Radiant Orders are specific, they are also broad. Everyone’s oaths vary slightly, but they each have similar themes to that of their Order. In the end, I think that it’s possible for people to have potential for several orders, but