Understanding the theme details in style.css

Prince’s answer is technically true, but doesn’t answer your specific questions. In the interest of getting you to learn more about WordPress, I’ll get those:

For Author, is that the blog owner, or the theme creator?

This should represent the theme author/creator.

Author URI, is that the blog owner’s personal website, or the creator’s?

Again, if the author = theme creator, this should then be the theme creator’s web site.

License & License URI, these are not open source. How do I specify that?

You can specify whatever you want, but themes inherit the WordPress and parent theme licenses. Learn more: