You have lovely things. Yes- as you mentioned, the chair in a neutral color would be amazing. Some end tables in cherry would work beautifully with your rug/ entire room. Optional- you can get an additional throw pillow that's already on your sofa for the new chair. It will "tie" the whole look together. Have fun and good luck.

You have lots of options when it comes to manipulating open spaces with color. Can you post some pictures of the rooms from several angles? If you shoot the view from each vantage point...what you see from the kitchen, what you see from the dining room, and views of all the windows and doors and openings...That would help us help.

I wanted to use Revere Pewter too -- based on photos I'd seen, but it didn't work for me. My local store stopped carrying BM paints, so I went to Sherwin WIlliams. We wound up with Agreeable Grey tinted a little darker at 150%. Accesible Beige was another color we looked at -- along with Anew Grey. I'd check those out. Next to the TV, I agree with moving the lamp to the other side of the room. I would put art on the wall, but before deciding on size or arrangement, I would look at a side chair there -- that could be pulled up for additional seating. Try one of your dining shairs there for feel and see if the idea works. You could have a small side table -- even a garden stool that could double as another seat if you entertain, and then fill in wall decoration. ETA I see graywings had the same idea was I was typing (and being distracted).

If you have trouble coordinating pillows, RH has some fabulous collections. They're ungawdly expensive, but you might do two special pillows and then find plain ones to coordinate. World Market also has some really cute indigo shibori-look pillows that you could pair with plain ones for a nice coordinated look.