Hey,
custom notification tone did even not work for me.

Here are my configuration:

Work mode: Whitelist
items in list: 2 (Facebook & Whatsapp)
default category: custom

silent: 0
chat: 0
sms: 0
email: 0
custom: 2 (Facebook & Whatsapp)
custom notification tone: my tone (could be played with, jolla music player)

best regards
az2111