In this case the media itself was being stored on a NAS drive, so the upshot is that your instructions will only have removed the database. The media folder might now contain duplicates of store purchases, the original files disconnected from the library, plus any that have been redownloaded, along with any orphaned files that weren't from the store and thus haven't been added into the replacement library. Also lost would be any ratings, play counts, playlists, etc. The consequences would be slightly different for those with an Apple Music or iTunes Match subscription, but overall the steps as you originally gave them could cause more problems than they solve.
The original error is particularly unhelpful as it doesn't give you the name of the file that cannot be updated. I suppose there might be a log file that could be examined but interpreting Mac logs is not a skill I've developed. I know this error sometimes occurs when syncing, particularly in Windows, and in that instance it can be usually be resolved by removing a folder called iPod Photo Cache which will then rebuild on the next sync. I've not yet established similar data for Music.
tt2