me too. just saw this thread. so much to read.
i feel its important to preserve this practice . also these kind of content quite lacking in english language.. any friends here willing to shoot a documentary with me?

do PM me

recently been reading - Voices from the Underworld: Chinese Hell deity worship in contemporary Singapore and Malaysia.

mainly about the DI YA PEK character channeled thru a tang ki (medium) - or i think some call it hei bai wu chang.
so talk about how this guy can become a medium how he inherited it..or more like how he was 'chosen'

"Underworld altars in Singapore and Malaysia are dominated by Tua Ya Pek
(Great Grand Elder) and Di Ya Pek (Second Grand Elder), the deities whose
original human names were Xie Bian and Fan Wujiu"

notable temples in the book
yinfu tan in klang.

the comparison with sg temples abit too much for me to digest ler.