Excellent insights and a well written article. One suggestion - it would be helpful if you explained how someone can tell if they have each of the SEO features enabled.
You could try my Chrome extension for this which automatically checks multiple pages at a time for technical SEO factors:
All the SEO factors checked for and the reasoning behind them are explained here (mostly based on advice from Google):
If you don't want pages to be indexed, you should use a "noindex" tag instead of robots.txt. It's a common misconception that robots.txt stops indexing when it doesn't. See:
https://support.google.com/webmasters/answer/93710?hl=en
> Important! For the noindex directive to be effective, the page must not be blocked by a robots.txt file. If the page is blocked by a robots.txt file, the crawler will never see the noindex directive, and the page can still appear in search results, for example if other pages link to it.
For small sites you can get use the free version you wont be able to save any results and are limited to the number of URLs you can crawl.