[DaveBlake]

Kodi v18 will work with whatever folder structure you have for v17, but users will benefit in the long run from rearranging some of their local artist art and NFO files.

...
I've noticed that the add-on Artist-Slideshow will download additional artwork for additional artists that I don't have music for.

...Now I don't have any music from Kanye West, but the Artwork-Slideshow will create a Kanye West folder, and then download Kanye West fanart and place it under the Kanye West\Extrafanart folder. So in my large collection, I have hundreds of these extra folders that don't have music, but have the Extrafanart folder in them.

I don't use any of them but I know there are other addons that do similar to Artwork-Slideshow, mixing extra folders in with the music, or creating their own folders. My hope is that we can move to having one consistent place, using common naming for both folders and image files.
 

Having a centralized database of this Artist information, keeps my actual Music folder location clean, while still providing all the benefits of the current system. This seems similar to the Single folder location for all the Movie Sets artwork, using the "Movie Set Artwork Automator" add-on.

I don't know about the  "Movie Set Artwork Automator"  addon, but yes keeping your actual music folders clean is another benefit of the Artist Infomation Folder approach (thanks for the reminder I've added it to my post).
 

So I'm guessing you will post where this setting is located in Kodi 18 (so us newbs know what to look for).

I'm shy like that, do all this innovate  work and then hide it from users

The "Artist Information Folder" setting can be found under Settings > Media > Music, pick a location of your choice. You also get taken to set this, if you have not done so,  from the music Library Export facility - export to library folders will create all the artist folders and NFO files for you. Also the "Artist Information Folder" setting  can be changed from the convenient "Settings" button that is shown on the OK dialog that is after you add a music source, asking if you want to scan to library.

Seriously I do need help to get a user guide together, with screen shots and everything, or at least a music "what's new" tour. But I have so much more I want to get into alpha I don't have the time to do documentation.