My theory as far as the gong is. Evidently the villagers believed that the gong had some kind of mystical power.
Enough to cause the villagers to fear it.
Maybe in the wrong hands what is in someways a good thing ends up tragic. It could be made to do evil along with the good and maybe they figured out how to use it without just hitting the gong.
The artifacts that they are mentioning might have to do with the gong,the treasure,the idol,the ruins and maybe the golden child may have something to do with the whole scenario.
And whatever VV3 has instore for all this will put it in perspective. There might be more artifacts to be discovered in VV3.
I had an Island event that one of my villagers had found a mysterious ball. The children wanted to play with it,It glowed. I decided not to to let them play with it.
It ended up being a crystal ball which made the girl switch bodies with another villager.
Some of the Island events have alot to do with magic. And I love the mystery of it.