From the frontend of the website, when viewing a page, the Cornerstone menu shows first Edit Page followed by Edit Header and Edit Footer. This makes good sense as the most common interaction will be editing the page content.
However, when viewing a layout page, the menu shows first Edit Header and Edit Footer with Edit Layout as the last item on the list.
Logically, I would put Edit Layout at the top, as it functions in a similar way to the Edit Page (and several times I have been on a Layout and accidentally ended up editing the header, as my click auto-piloted to the first item in the list).
Would others agree?
The hierarchy for my use across many websites so far definitely puts Layout above Header or Footer, and much more in line with Page or content pieces.