The Nine-O in the original post would not be a comfortable desk chair for most people. I got the arm chair version for my mother for a few very specific reasons. She was almost non-ambulatory and needed an armchair to be able to push herself up. She was slowly wracking the wooden armchairs in the house apart by putting uneven pressure on them and loosening the joints. The Nine-O is very lightweight and it is a solid unibody frame. It also has a high firm seat which is good. But the back is low. It was a good chair for someone like my mom who was about 4'8'' and 120 lb. when she died. I am very small myself and find the back is not really high enough for long term sitting.

I can see that you already have lots of input but I might as well add our experiences. I had two desktops before I switched to a laptop. I would never go back again. It is great to be able to use it where ever you are. We have our house set up to be wireless. So my daughter and I can both use our laptops. The printer and router are set up in one of the bedrooms, which I rarely see. We could make the printer wireless if we wanted to but we don't use it often enough for it to be an inconvenience to just go to the printer with the laptop and dock it for long enough to print what we need. As for the keyboard, I think they have as you mentioned some extensions that you can add, but you are right, to keep it portable, you have to keep those to a minimum. I don't know if any companies make the natural keyboard. I did want to mention that we bought the extended warranty with our last laptop and then extended it another year to the maximum allowed which expired in March. So we are almost to 5 years on this one laptop. In that time, our warranty has covered everything but a replacement cord or battery. We had the whole motherboard replaced at one time and a new screen in year four. No additional cost beyond what we were paying for the warranty. If you still want a desktop station, you might consider wireless and that would allow you to use a rolling cart and not have all the wires to deal with. pm2

It's not a "captain's chair" it's a basic rolling swivelling desk chair. Used in schools and offices for people who weren't important enough to get the leather upholstered ones. Check the hardware for any patent date - it can't be older than that date, but it can be decades younger.

I would not go to the trouble of remodeling the fireplace. Simply hang the TV above that nice distressed cabinet to the left of it, on an articulated arm so it is easily adjustable. Opposite, where the desk is now, angle a comfy chair and floor lamp for a reading corner with a view out the French doors. Place a small scale sectional and coffee table basically the same way yours relates to the FP in the current family room, and the short wing of it will create a pathway between the two opposite doors. For the new office, consider painting the desk. A rich green, teal, red (or a color from the wallpaper) might be nice. Place it opposite the FP where it can serve as a visual counter balance. Add a nice big upholstered swivel desk chair to give sufficient weight to the desk. Add a pair of smaller armchairs flanking the fireplace. Then we can measure for rugs, rearrange the art/mirror and tackle the lack of good lighting.