Sounds like you have three very good choices to choose from.
Soiree
I haven't tried Soiree yet (my neighborhood too), although nr706 seemed to like it enough:
http://www.lthforum.com/bb/viewtopic.php?t=5700
For others reading this post, the parking lot across from Bisto Campagne & Tank is a great place to park for Soiree when you think that street parking in Lincoln Square is difficult. There are usually spots available. If not, head a bit east on Wilson.
Scylla
I was just at Scylla last week and I thought that the food and atmosphere were outstanding. I had an excellent piece of fish (monchong) which was served with veal sweetbreads, and I also enjoyed my taste of my companion's scallop entree. We also very much enjoyed our appetizers (apple and celeriac soup & mixed greens salad). The chocolate panna cotta w/ salted peanut ice cream was fantastic. The menu consists of primarily seafood options, but at least one vegetarian entree and one poultry entree, as well as at least a couple of vegetarian appetizers:
http://www.scyllarestaurant.com
The restaurant was not loud, although it was only about half full so I can't address how they would have handled us if it were crowded (the pacing of the meal was excellent) and I can't tell you how noisy it might get. My only complaint was with the service of the entrees -- the bus boy brought out the entrees and given Scylla's price level, I would appreciate the waitress bringing out the food and explaining the composition of the course. In my case, I was especially confused because I did not see any sweetbreads on my plate, but before I could say anything, the waitress came with a separate small plate of just the sweetbreads and without apology, explained that they had been forgotten in the dish and put the plate down on the table.
Even given that complaint, I can't wait to run back to Scylla . . . the food was that good, and I think better than Spring (also more quaint). However, if you plan on having three courses, it will likely cost more than $40 (you could easily do two courses or split appetizers/desserts and be under $40, exclusive of wine). The portions were quite large, especially my monchong which consisted of two decent size fillets.
Schwa
I've been to Schwa once (last month) and enjoyed it quite a bit. It's so small, but you probably know about the atmoshpere since you dined at Lovitt. The byo nature of Schwa is so appealing and the service was fantastic -- very friendly and professional. I also enjoyed the food quite a bit (especially the pork tenderloin/belly entree). However, as you would expect, the menu is a bit more limited. I also found the room at Scylla to be more comfortable.
If I had to choose between Scylla and Schwa, I'd use Scylla (and that says nothing negative about Schwa). As for Soiree, I hope that it's a good addition to Lincoln Square -- can't wait to try it.