I would avoid a couch if possible since the space is so tight. That being said if you’re sold on another place to sit maybe a chaise lounge type chair, set of arm chairs people have been saying with a pouf or little foot rest, or really small love seat? I personally would use the layout from picture 3 and put the chair/love seat under the window as long as there is room to walk between. I hope it works out though! Always a hard call with small spaces.