Missing album artwork / iTunes 12 not correctly synced to iPhone

Question

Hi all.
Earlier, I simply wanted to add a couple of albums to my iPhone 5S (running iOS 8.1.3) that I purchased on CD.
After being unable to add the songs due to the commonly occurring 'ghosting' issue, I checked on my iPhone to see if they had appeared in the Music app. They didn't.
Instead, most of my album artwork was removed, seemingly at random. First thing I tried was deleting and manually adding a few of the affected songs. No luck with that. Secondly, I restored the iPhone from a backup. Again, nothing. I again tried to delete and re-add the tracks, which still didn't work.
Frustrated, I decided I'd just delete all the music through the usage menu on the phone and manually re-add it all. Here's where the main problem occurs: iTunes still lists 8gb and 900+ songs still being on the iPhone despite there being none. I figured this must be part of the issue, the iTunes troubleshoot menu lists everything as being fine, so I decided to update iTunes. Yet again, no luck.
I'm hesitant to delete the "music" on the phone through iTunes as I assume it should detect the music being removed, and I feel it would only cause further problems.
Essentially, after attempting to add 2 albums I'd recently bought and ripped off of a CD (though iTunes), it would not add to the phone and instead is only listed through iTunes with the light grey writing. This randomly broke most album art on the phone, and after restoring the phone/updating iTunes didn't work, I deleted all music off the phone. iTunes still lists all the music as being on there.
Running the latest version of iTunes on Windows 7.

Answer 1

Generally if syncing doesn't work as expected take the following steps:
Backup device.
Restore as a new device.
Restore the backup made earlier.
This assumes all content on the device is in your library. If that isn't the case see Recover your iTunes library from your iPod or iOS device.
tt2