First, I spent almost an hour trying to figure out how to simply format the map layout legend to have a white background(fill) 10 points larger than the contents of the legend. And add a black 2 point outline 10 points larger than the contents. This used to be a simple right click > frame tab > make changes > "ok". Now it's a convoluted workflow that I never did get desired results.
To add to the frustration, clicking "apply" does not apply the most recent changes, making one think they didn't find the correct workflow. It applies two changes prior. I found this out by trial and error. I never could get it exactly, even using the help section. So I was forced to give up under time constraints, and recreate the map in ArcMap.