Could do a lavender accent wall. But dont want too much lavender. or lavender walls with a plum accent wall and white curtains. And instead of the chandelier possibly could use icicle style Christmas lights around the ceiling of the room.
Now this is gorgeous interior design. I love the black and white theme and I've never seen a dining room with a couch. I can't picture myself putting a couch/secondary seating area in my dining room but i guess it works here.