Does EnableRankingInformation work with the Sitecore Free Edition?
Following the instructions on the page do not work.
It works but the UI in the linked documentation is the .Net UI. Coveo for Sitecore uses the JS UI. Thus, you won't see the "Show Details" link and the "Ranking weights" tab.
To see this information in the JS UI, you need to press the Left Alt key while double-clicking on a result to open its debug modal box. The ranking information is at the bottom of the modal box content.
Yes, it is supposed to work.