I am Mongolian, and I heard about Lus and Savdag from my prof& went to investigate too. I was researching magic for my master’s’ thesis in human ecology to see if there was any ecology or conservation reason behind some of these “superstitions”.
As for the apparitions in the room, we were living in Bangkok at the time, but my sis left for a local meditation camp somewhere around Pai. She was adamant that after she became - for lack of a better word- more sensitive after spending a month learning niche, somewhat scary meditation techniques with the Thai monks. She habitually woke up to a bunch of people in her room who usually never did anything or never even looked at her. But back in Bkk, there was one time, a woman interacted with her. Ofc she was scared out of her wits and she said she actively worked on not having these apparitions anymore