This is just my opinion so take it for what it's worth. I love the idea of through the wall aquariums BUT in your case if it's going to compete with the tv and fireplace I would find another place for it. ONLY because your gonna put so much time and effort into your tank, get it looking just right and be proud of it and your fish that are in it. I would want it in location where it would be the focal point in that room.
Like mine, I have it against the wall in our living room but on the opposite side as the tv and windows. So if your sitting on the chairs or little couch on one side your view is the tank and a picture of my 2 month old son. If your on the big sectional your viewing the tv and hearing the nice water effect of the tank.
Make sense? And again just my opinion.
Good luck with whatever avenue you choose.
"When creating an aqua scape, strive for the beauty of imperfection, as its art and there is no wrong or right, it's left open for interpretation" James Findley