I think the sofa makes most sense on the wall that the 2 windows are on but can you post more photos of the room in all directions?

Post a floor plan with measurements.

I suggest putting the sofa by the 2 windows. Replacing the futon with a chair and putting that and your current chair so that they face the sofa with a coffee table in between. Put the piano on the wall where the desk is now (by the cow rug). Keep the tv on its current wall but put it on a swing arm so that you can rotate it the direction you need.

I would also try placing the piano so that it faces the window and sort of seperates the living room and dinning area. That might not work but I would try it just for kicks.

Can the piano be moved down the wall to right giving you more space in living room area? Personally, I like the couch facing the tv. If you move the tv to the wall where you have the craft paper, can you turn the couch to face it or will it block off your walk way?

I would put the t.v. on a console where the piano is now, the sofa opposite, move the piano down the wall to the right as suggested and add two chairs in front of the windows or on either side of the console, or opposite the windows in an L shape with the sofa. I would eliminate the futon.

Did I miss something? What happened to the nice red rug?

First things first. To keep the piano tuned and healthy, it cannot be on an exterior wall. If it is played, then move it to the interior wall of the walkway area where the tall, leggy piece is now, and hit the 2nd hand stores for a real piano stool or bench. If you don't play it and it is too long for that wall, I would sell it. Hang the circle candle sculpture above the piano or on that wall even if you sell the piano. Move the futon to the wall opposite the piano and add a floor lamp for a reading/lounging area. Hang a big, colorful piece of art above it. Get replacement legs for the tall leggy piece and bring it down to a realistic height for a TV credenza - no lower than 18" or higher than 24". Put it where the piano was with the TV on it. If the rug has a side that is wider than the sofa, turn it so you can put it under the front 1/3 of the sofa. Float the sofa perpendicular to the front windows and use the upholstered bench with a tray for a coffee table. Put the skinny legs that you've removed from the other piece on your ironing table and use it behind the sofa for a sofa table. You might want to paint it (chalk or enamel) and set your corn plant on it to add life and a bit of screening behind the sofa. Put the bookcase from the dining room between the two windows, and angle the chair between it and the TV credenza. Remove the skimpy curtains and, depending on your need for privacy vs. view, use fabric roman shades or top down/bottom up shades on all windows in your room. Use the sisal rug in summer and the red one in winter for the seating area. Save the flokati for beside your daughter's bed (unless it is actually the dog's bed in the living room) and the cowhide in your bedroom. Remove any pieces of furniture that are at knee level or lower, and take most of the plants outside when weather permits. The biggest one and the corn plant could stay inside for some green relief.