Love the five different area of investigation that you went over, great way to analyze and diagnosis the issue. I would also definitely agree doing a rankings comparison between the two time frames, and not only check what your Google ranking is, but also track the search volume for your keywords to see if it has fluctuated or gone down. Google Trends is a great tool for this as well, as one of your keywords that your ranking for may have just lost popularity online.
IMDB: This site is #1 when it comes to movies and TV shows. Getting a link from IMDB can be worth a ton of value, but they don’t link out to just anyone. However, that’s not reliable or even plausible for most people. Instead, you need to turn to the one location you’re free to post; the IMDB forums. These forums have a huge audience and narrow topics, and like Reddit or web forums in general, they can be great places to show your expertise, link to your content, and promote deals.
Now we have a list of landing pages for only visitors that originated from organic searches. Using this list, you can begin to explore your site content and better understand how the search engine is ranking your pages and where some of your traffic is originating. In addition to that, you can also see valuable information about how long these visitors average on the website and how many other pages they view after their initial landing.