I love the clean, uncluttered look of your home and you've made some great furniture choices. My first thought, though, is that I would try to rework the sofa/sectional placement. It really is unwelcoming looking to me to have the back where it is facing a wall, when it could be oriented to look into the room and out the windows. It seems like if it were placed in the corner under the stairs that it would feel open and invite you to come in and sit. I'd hate to be cooking in the kitchen and have the family or guests with their backs to me. If you are having a TV in another room close by, do you need one in that room, too? If, so placing a 70" unit will probably only work as you have it. But, to me, it's not going to look like a living room but more like a movie theater, which is fine if that's what you're going for. It seems like it won't be a cozy conversation area, though. I might actually flip the rooms and put the dining room where you have the sofa now. I was looking at lights used with dining rooms and ghost chairs and saw this, maybe would work in the living room? Kind of fun. don't know if it would look as good without the colored walls though. And I thought something like these were interesting to consider for over your table:

Ryan...here are the links for the items I put in your room. The cabinet is an antique...I put it in your room because you wanted a touch of Asian:) https://www.potterybarn.com/products/dara-print-pillow-cover/?pkey=call-pillows-throws-slipcovers&isx=0.0.11435 https://www.potterybarn.com/products/navin-print-lumbar-pillow-cover/?pkey=call-pillows-throws-slipcovers&isx=0.0.11435 https://www.westelm.com/products/color-wash-coffee-table-h2945/?pkey=ccoffee-side-tables%7Ccoffee-tables https://www.westelm.com/products/lucas-leather-swivel-base-chair-h1545/?pkey=cliving-room-chairs%7Call-living-room-chairs https://www.crateandbarrel.com/owen-matte-brass-floor-lamp-with-brown-leather/s216095

Having had a "setee" which is just a loveseat by another name, I can vouch for it not being very practical. Two people can sit at it, (and they will and have in my house) but unless they are very good friends or related, it's not going to be their choice, particularly if they are doing something like watching TV. Sipping afternoon tea, maybe. But if you don't need a lot of seating, then their small size is great, particularly for curling up with a good book. It's easy enough to throw in a rocker or some other smaller less padded chairs to add extra seating. I use the end chairs from my dining room set, since unless I have guests, they make it difficult to get around the dining table in my small dining room.

I want to thank you all for your suggestions and close out this thread. I've moved into my house with the furniture I have, and this has allowed me to see what I need and what could work. One thing I've learned is that I'm really lacking in storage space. So now I'm obsessed with the idea of storage ottomans and tables. To that end, here's what I plan to do. (Sorry that my sketching isn't as nice as your models!) Add a counter-height table / island along the open wall space in the kitchen. The ideal one would have drawers, shelves, or cabinet space and also be able to accommodate 4-6 counter-height chairs (or maybe a banquette and several stools), or better yet, be expandable. This would be my primary dining area. Get rid of my current glass-top dining set and move my beloved coffee table to its spot, where the kitchen opens into the living room. Get four ottoman / cushions with storage. This will be casual tea time seating or extra entertaining space. Place a new sofa along the long wall for my primary lounging space. Full length (not apartment size) I think would work as long as the seat depth is relatively shallow. Buy a long, narrow storage ottoman / coffee table to go in front of the sofa. The ideal ottoman / coffee table would also be able to serve as extra seating for larger gatherings. Keep one of my benches under the front window. That's where it is now, and I think it works quite well there. The other bench is upstairs at the foot of my bed. The window bench in theory is my current lounging spot, but in reality is a really fancy dog bed, LOL. With this plan, I could seat about 15 people for casual gatherings and have plenty of standing room space. That's more than sufficient for me.