We have had some really comprehensive discussions on this in the past... all buried with the old forums (which is hopefully going to be back for referencesometime soon?).
I think we were making some real headway into setting some guidelines for VGM additions.
But for now:
Official soundtrack releases should be added as with any other release.
Files ripped from the game itself should be added with the actual physical (or digital) game release date/label etc that the files came from.
Here's an example: https://beta.musicbrainz.org/release/155c9913-9c34-4514-93f8-d6ca679673df
I don't think we'd reached consensus on this so there's probably elements of that release that people disagree with, pipe up if you're one and you're reading this!
Fan-made covers have no place on MB unfortunately, I used the actual game package cover in that previous example.
The exception would perhaps be if someone released a highly-circulated bootleg of the game audio, with a custom cover (eg a very widespread torrent/blog post). Then I would add that as a separate bootleg release with the cover and track titles that the bootleg came with.
For game rips track titles can be tricky, I think generally we use either the most accepted/widespread fan titles or the file names themselves(or both, via a pseudo release). If the track has an official/known name, we use that.
That's all I can come up with off the top of my head...
These are the two 'game rip style' discussions on the old forums (that I was following), just in case they come alive for future reference:
Any other specific questions, I'm sure people will have input!
I see you've already added heaps of VGM, thanks for that