I have no idea what you are talking about..? Yes boo camp is a great exp grind stage for Conquest especially but it also has dialogue that suggests it was originally a festival (similar to that of a harvest festival) that was attacked by Faceless
No, it's canon. It was in the DLC itself, there's official artwork of it everywhere. They did a poll to decide which male and female characters people wanted to see dressed up for the dlc the most and he was one of them