When you say the rug in the living area is going away, do you mean the w/w carpet is going to be taken away everywhere we see it in the picture? Is there hardwood under the carpet or what will be there? Leaving about a foot of space between an area rug and the wall is a good look. I prefer big rugs in big spaces, especially under a dining table. Too small, and with a table and chairs on top, it looks odd to me. I have a LR and DR spaced somewhat like yours. I have two oriental rugs that complement each other, but they don't match. The space between the rugs is large enough that each (and the room furniture) defines its own area. But if you had two great rugs that matched, I think that would be fine, too. Any links to show us? How about a floor plan to visualize the floor space better?

I can see the option for a longer sideboard but if the shorter one were centered & had appropriate art above I don’t see why that wouldn’t work. A super long pice of furniture is great if there is one that makes your heart sing & it fits and you need the storage there ( & who doesn’t need more storage) , but then it’s less versatile, harder to move and usually much more $$, fewer options, so I think most people likely to buy cheapo item.

It depends on what the rest of the floor plan looks like and the relationship to other rooms. In other words, is part of that family room space actually going to be used as a hallway to another room? If so, 17’10” x 18’2” might not be big enough. In my previous house the family room was, in theory, 22' x 21' but it included "hallway" space on 3 sides, so you were limited on the actual area for furniture placement and the furniture had to be floated. Most of the furniture was on a 10' x 14' rug. In the house we built last year the family room is 18' x 22' not including any "hallway" space. I now have 2 seating areas, more furniture in the space and only the front legs of the sofas are on that same 10' x 14' rug.

I think we only have one part of the question . All you will get here is hundreds of pics from beth and you still will not have an answer . Post pics of the space and the table . A pic of the LR so we get some clue as to your style and if you have a fixture you are considering post that. BTW all those are added in a comment here not new posts