I have issues also related to this issue, basically in the same form. I'm really frustrated by iCloud rarely working as advertised and providing very little info as to why issues are occurring.
I can navigate to the files created via Finder to the Mobile Documents folder of my simulator, but they never show up in the Files app in the simulator. None of the .plist entries given above seem to do anything in terms of what might be seen in the UI.
For example, when I go into settings and iCloud, it does know that files associated with my app are in iCloud.
Topic:
App & System Services
SubTopic:
iCloud & Data
Tags: