In the last picture, does the door on the left lead to the garage? So will you be leaving the tile floor there? I wonder if you can't leave the living room arranged the same as it is now, but with the chair where the tv will be vacating? It doesn't seem to bother you now to watch tv on the angle. Although, since you are losing the half-wall, you can just put the sofa across the room, between the kitchen and patio door. That creates a walkway along the long wall. This is how we had our FR arranged, though where you have a bookcase on the right, we had doors to a powder room and a laundry. If your new sofa won't provide enough seating, add a swivel chair or two, either in an L to the sofa or by the bookcases as you have now.

Beautiful sofa. Can you move the old sofa to the den? Consider moving the gray credenza to the wall where the mirror is and moving the TV to that wall and lower. Then you could have some art of the fireplace and a better view angle. A rug is needed to ground the space. I like the chairs in this inspiration picture but two swivel chairs would be good in your room also. The mirror reminds me of your mirror. I like the small round table for you and/or some c-tables. You will need some patterned/textured throw pillows, too.

Thanks for the suggestions, Nancy! Putting the dining table on the side like that helps with the "choke point" that we currently get between the table and wall in the centre of the room. Any suggestions for what you would do with the extra space towards the kitchen, since the dining table is no longer in that space? I agree about the bench: We were thinking about getting this table: https://ca.transformertable.com/pages/the-dining-set which has a matching extending bench to go along the window. I don't want any built in units on the ends because I want to be able to extend the table across the majority of the room when a lot of company is over.

In a space this large I would do 2 seting areas. But you need to provide a bit more info. Do you need a TV here ? how many seats on a regular basis are nessessary? My space in these pics is 15 x25 but as you see we have a huge FP but it might give you some idea of arranging furniture You could certainly use the wall where we have the FP for a TV, storage display idea.