The black sofa could be considered a neutral, and therefore will go with just about anything. Do you like the white and gray, or are you looking for color? Bright colors? Subtle colors? Also with a baby I would surely want an area rug for her little knees. In this first picture you can see pops of red were added for color: [houzz=https://www.houzz.com/photos/2007-aso-decorators-showhouse-and-gardens-contemporary-living-room-atlanta-phvw-vp~26704] In the second picture, a monocrhomatic color scheme with a soft area rug: [houzz=] And in the third picture, yellow was added for interest: [houzz=]

A floor plan would be helpful for space planning.

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 .

Give search for home theatre door in houzz and it will give you a few ideas. But finally what you have to think or take help from interior designer is about the theme of your home as this door should also get aligned with your house theme. In general having hallway as part of home theatre is not advised so if you can change it, it would be better. But if you can't then at least install auto closure.