Based on the information and what you're trying to do, all you need is the sunny day and the blinds open. You will have plenty of light to evenly light the couch, you won't have shadows, and the right exposure will render the wall white... because it is. Therefore, I would suggest that maybe this is being a little over-thought. You have the lighting, the couch, and the camera. Maybe take one or two shots bracketed over the 'correct' exposure and see if that helps. Really, if the wall is evenly lit enough from the windows, you could probably do a color selection in PS and remove it completely and replace it with a white color fill. That would really make it easy I would think.