More information than standard "Site Details", also to be available as tokens Is there a way to add additional fields to the config/system/site-information area such as business owner, "business location", "hours of operation", "phone number", etc. I would then like to be able to use that information throughout nodes and blocks as tokens.

That way if the details change, they will change throughout the site. This is particularly handy when using token filter for document templates on uses for multiple sites, like privacy statements.

Is this possible, or is there another way to add this functionality?
I wrote a tutorial on most of this: http://www.jaypan.com/tutorial/drupal-8-extending-core-configuration-extending-core-forms-and-overriding-core-routes

I didn't get into creating tokens for the new items, but you can do it by implementing hook_token_info_alter() and declaring the new tokens as part of the site tokens, and implementing hook_tokens_alter() to set the values from the config you create following the tutorial.