Twins...
As I see it, you are really working with a usuable space of 19'' x 12'. Though your side wall says 16' you loose 2.5' with the fire place, plus the kitchen bar jets out into that room by about 1'. Best that I can estimate, then you need a walking path so you can go from your kitchen area through your GR to the front hall area. Thats another foot or so. That means you'r loosing up to 4.5 feet when planning your area.
The fire place really breaks your GB into 2 small areas or on large one. My first suggestion would be to hang the TV over the fireplace. that will make one focual point in your room, not two like it is now. The benefit would be that you can view the TV from the kitchen and the GR. If you place your new smaller couch facing the fireplace that will give you more room behind it so you have a walking path. I can't remember the furniture that you have, but then you might be able to put you 2 chairs in the corner where your tv is now, and an additonal chair or small couch perpendicular to your couch facing the fireplace.
An other option would be to place the 2 chairs perpendicular to the couch facing the fireplace forming an L shape with a table in between the chairs. Electical plugs become a problem because your furniture is sort of sitting in the so called middle of the room. Where do you run your lamp cords etc? My furniture sits way in the middle of the room so we had an electrical output installed before we put our foundation in. However, you can run the cords under your carpet. You can either do it yourself or have someone do it for you. Its done all the time. An other option is to place an area rug over the cords that you put on top of the carpet and run it from your lamp to the outlet.
Here's how I figured out how I wanted to put my funiture before I did it. It saved me from breaking my back. I took measurements of all my furniture. Width and length...making sure I wrote everything down. That was the most important step for me Then I took sheets, folded them to those dimensions and laid them on the carpet where I wanted those particular piece of furniture to be. AfterI was all done, I was able to "walk the room" to see how the placement felt. Sometimes I liked my ideas and sometimes I didn't, but at least I didn't break my back doing it...BTW, I never have help, I just do it myself.
Also, I have taken tape, like packing tape, and outlined the furniture on the carpet instead of using sheets. I'm a very visual person, but sometime what i draw out and like on paper doesn't look really good when its done for real. A really long and narrow room, which is what you're working with is the most difficult to decorate...most professionals will tell you that. I had several nightmare rooms that I never liked. I've moved 14 times in my adult life. My nightmare rooms could have looked better knowing what I now know. And I had to really fussy on getting this house right.
Now I need to figure out what to do with my walls. They are very high...14' and what I have done in the past doesn't work with these rooms. A bucket of paint and some courage is really all that is needed. Fear of being perfect is what is keeping me from doing it. But I'm working on it.