Have you looked into a dehumidifier, sizing the AC to handle the moisture, or a energy recovery ventilator?

By placing the tv on the longest wall on left and placing the couch parallel facing the tv you may have room on the back of the couch to put a long table or preferably a chest with drawers..this would add always needed extra storage at the handy location at the bottom of the steps..this concept creates little rooms within a room and enhances the spaciousness of the open concept hall

HI -- Well this is a nice floor plan but it creates problems . Because the space is all open doesn't mean you have to put the living room or the dining room where indicated on the plan . Also where you have marked for the sofa is not going to work there . Not enough room and in the way of getting to the bathroom etc, I do think you may have to have a free floating TV stand between the living -dining rooms . You could have the TV on the wall beside the kitchen and have the sofa facing or on the left wall and the dining at the front . I would put the TV on the left wall near the entrance and have the sofa facing it , leaving a hallway walking space behind the sofa . It's too bad the front entrance is on the left . If it had been on the right then that would be better flow into the center of the main floor . If you do decide to have the TV room divider where you show on the plan , keep it right over to the left wall as a room divider , then it won't cut the room in half so much and it keeps the stairwell open . Remember , you do not need to push the furniture against the walls .

For your office , you can go for the right side second entry from the main entrance of your house. This way you can make a full glass, sound proof, no disturbance and a comfortable in house office . you can have one more entry from inside for the easy accessibility for the personal use. In your dining area,there's a door leading to the balcony. Make it a 3 track glass door for the good daylight and a natural view from your hall also. In the kitchen, make your washing area of the size 10'8"x 4' . This way you get two perfect rectangle for a perfect planning for the kitchen as well as the washing area for utensils and washing machine.