I don't understand what all the hubub is about. He has everything he needs explained in his first post.

As has been explained, the ID41 is only for Sooloos or Roon. Just use the Macbook with JRiver to play the music from the NAS. Plug the USB of your Macbook into the MQA card instead of the ID41. Unless there is something about MacOS not working with Meridian that I don't know about, all should work just fine with nothing extra needed.