I would not sit at on banquette with the idea that there would be someone sitting up and behind me, throwing things down my shirt, laughing at my bedhead from above, and generally breathing down my neck. I get enough of that at the movies.

I do like the idea of shelving. That makes it a nice architectural piece.

If I understand correctly, the banquette will be L shaped and one side of the L will be against a wall and another will be open to the family room. I'm not certain what options you have for the banquette, but you might consider upholstering the whole thing so that the open back to the family room looks like an upholstered piece of furniture. You could then put a console table or shelving behind if you like, but either way you'd have a nice finished back to look at.