If the wall between the two rooms is not load bearing, then taking it down is fairly simple. If it is load bearing, then a beam of some type will need to be installed to carry the load that is currently held by the wall. Someone with experience in house framing can tell you if it is load bearing or not by looking at the wall from the attic if it is accessible. If it is a 2 story home, there is a great likelihood that the wall is load bearing, and that presents a different challenge, and may require the new support beam to protrude below the existing ceiling line.
I would like to see what is to the left of the fireplace in the corner, I think the Darrieux would work nicely there if there is space.
My personal preference with the fireplace would be to either cover the whole thing with sheetrock and build a new wainscot and surround to compliment the darrieux, or skip the wainscot and just build a mantel surround that really stands out and compliments the space. I'm not a fan of putting TV's above fireplaces in general, but if the mantel were a bit lower it could look pretty good. I would also completely demo the hearth seat, and use high heat black paint on the inside of the fireplace itself.

The attached picture is a fireplace I did in 2005 in a similar fashion.

I can't see the relationship between the 3 photos you've attached. Opening up living and family room would create a more open concept design.

Not sure which wall you are thinking of removing?
Have you selected new flooring for the concept you want?
Best to you.