[Karellen]

3) Cover Art -- "Embed cover images into tags", and "only embed a front image"

This one is questionable. My experience is that a lot of the times you end up with low quality images embedded in the file.

1) [Music layout question] I didn't try any compilations, various artists, soundtracks, or xyz other thing I can't think of yet. Given I want to have all pretty stuff local am I good to go (to tag/scrape 10,000 songs) or did I miss a step?

Nope cannot see any steps missed. Have you been through the guide? I think you have judging by some of the comments... https://kodi.wiki/view/HOW-TO:Create_Music_Library
"other thing I can't think of yet" might be Audiobooks (wiki)

2) [Music layout question]  Before I start, do I need to setup the separate artist folder?

First scan the music file tags. This means disabling the setting "Fetch additional information during update".
Once your music files are scanned into the library, Kodi will have a list of artists.
Using section 3.4 run an Export to create your artist folders... https://kodi.wiki/view/Import-export_lib...lders_only

4) [Skin question] I couldn't find correct link that didn't fork 20 times that a noob like me could follow about making my music section look awesome similar to. If there is a guide that isn't 5+ years old can you point me in the right direction?

What in particular do you want? The images look like standard views in Aeon Nox Silve so you shouldn't have to do anything special.
Of course you stated you don't want to connect to the internet, so you need to figure out how you will obtain your local artwork and save it correctly... Music_artwork (wiki)

I wouldn't be scraping all 10,000 songs at once without testing a little bit first.