Korea starts the game as "Eastern Buddhist" with "Confucianism", "Flower Garland School" (Hwaeom), and "Musok" as their adopted sects.
The Joseon Dynasty starts with Sanjiao religion with "Flower Garland School" as their sect and a later event about persecuting buddhists that changes Flower Garland to Musok.

Source: My ass, but this is probably how it will go.