I could see it happening... if we were going into Hingashi or further into Othard.
We're going to a mesoamerican-themed "new world" continent.
Thematically, Onmyoji wouldn't fit here, considering real world parallelisms, something like Druid/Shaman would make more sense.
Then again, this is pure speculation, and since it's a fantasy setting they can justify any job being from anywhere.