Especially now since there are not so many people walking by. That may be your best bet - I can't think of any lounges at DTD that do not include loud or live music.
You might also try the bars at Portobello or Fulton's, don't think they do the music thing. I do not think these count as separate lounges, they'll be inside the restaurant and I don't know if they are just a bar or if they have tables and chairs available. Love the bar at Rainforest Cafe, personally, but I don't think it'll be quiet.