A:Answer Yes. Ideally, run all of your media devices through the receiver.
While the most recent iteration of eARC will support most digital formats and drive 5.1 surround with no problem, you will not be able to play high bitrate formats like DTS:X or Dolby Atmos. Additionally, many TVs (especially ones a couple years old or more) downgrade the audio signal being sent through eARC.
All of these problems are solved by running all of your devices through the receiver and letting the receiver function as a tuner. This is really what it is designed to do and it does it well. Save eARC for if you stream content from built-in software in the TV and therefore cannot run that signal through the receiver (like a RokuTV or similar).