I finally figured out what it was. It was bad CC called "SYB_Record_Player_With_Christmas_Songs.package" that was interfering with my base game stereos and walls speakers. It was throwing an Exception every time I tried to play the Soul station on my (non-CC) wall speakers and radios. I have deleted that file, and the Soul station now plays normally.
A separate piece of bad CC was causing the wall speakers to not play at all (no menu option other than "upgrade" and "salvage for parts"). I narrowed it down to an item I had by Slox, but I have yet to find out exactly which piece in my Slox folder caused that. I noticed there was a JSON file in that folder, so I deleted it and started loading the CC back in small batches.
Update: I unmerged a Slox package file which contained the American Diner CC. Within that CC was a radio bundled in there. I deleted the whole folder, because I suspect the radio as being the culprit. None of the other Slox items I had gave me any issues when I loaded them back in, so I think it's the American Diner radio that caused the second issue.
Thank you for your help! ❤️
