Plex does not issue a warning about the file not being uploaded (however an error is hidden in the logs). Check if your files are actually uploaded by Plex before deleting them from your device.
I have used RSS/Atom feeds for ever, recently I have decided to ditch Twitter's client and for Twitter feeds consumption I am using twitrss.me to parse twitter user feeds. I need to find a good parse for FB and than I will be a happy man.