The article is very interesting @slowwalker, After reading your post about:
3 sacred figures were result of the negotiation between the Folk traditional religion and the Buddhism. I had posted on that before. At the time of introduction of the Buddhism, the ancient kingdoms were formed in Korean Peninsula. The Kingdoms needed ruling ideology, they wanted to use the Buddhism as a national ideology.
So they needed to mitigate the folk religion. The result was the mixture between the folk religion and the Buddhism. But the Buddhism had superiority over the folk religion.
Actually this problem has happened thousands of years ago across the region, For the sake of politics, Politicians use religion and customs.
The same thing happened in korea, at the time of the Silla dynasty, Mishil taking advantage of religion for his political interests, So the queen of Seondeok separated religion and politics at that time.
You are really specialist in Korean history
LOL...... I just read a bit about that history, at that time I was looking for the source of thousands of ceramics found in aceh, 70% came from the tang dynasty and the ming dynasty, and it's very close to .korea,