You have a dark room. I would remove the shades from the windows. Natural light makes things look so much better. If you need privacy at night add grommet top panels. Also, you need lamps. Do not use overhead lighting.

Thank you for posting the new pics! You could put a table and lamp where the sofa and loveseat come together. I would do another table and lamp at the other end of the sofa. If there is not enough room for the table just get a floor lamp. You will need enough lamps so that everyone in the seats can see for reading.

What area were you planning to use the gallery wall. I don't see any space large enough to do that. I would take down those frames over the TV and put a nice large piece of art over the FP. And lower the picture on left of display cabinet.

Or add a big mirror over FP