That seems logical to me. When someone performs under a lot of names like that, each one is a separate artist. You have a useful example there of how they link up. This matches how Discogs does Aliases. MB has an Artist for each, linked back with a relationships to the Real Name
Sometimes an artist keeps a single identity, but performs with the odd alternate name or spelling. Or started out with a different name. In those cases you’d just use a “Artist as credited:” and rename them for just a few tracks. Those tracks then still appear under that artist. That is more like the ANV of Discogs.
The album was released by Promo Only. On Discogs, Promo Only has various sublabels for its series. For example, Underground Club is the series this album belongs two. So the question is, should this be a label on MusicBrainz, too, or a series? A search shows that others have entered series.
For the release title I followed the example at Discogs. However, I think based on the cover, “Promo Only” is not necessarily part of the title. I see these two alternatives:
Underground Club: August 2000
I think the titleing also depends on whether you consider “Promo Only Underground Club” to be a seperate label or not. If yes, then “August 2000” is the title. If not, then “Underground Club: August 2000” is the title.
1\ That is up to you. Adding the new Series would be helpful to others. As you have spotted, some of this label already has some Series setup that you can use as a pattern to follow. But as this would be a series of just one you don’t need to worry.
2\ Adding an Alias to the recording can be useful. Generally we give the recording the name it is known as on the first official single\album release by the artist. Then alias the other options.
3\ With the title, I’d follow the pattern of other releases on the label. The text is all prominent on the cover. Promo Only: Underground Club, August 2000