When is this dinner? The seating at Bacchanal is all outdoors. It’s pretty chilly right now.
If you are looking at the Bywater specifically, there are plenty of options. Bywater Bistro is the current hot favorite (I have not been there—same restaurant group as Compere Lapin which I was underwhelmed by, but people rave about both of them). They will take reservations and you will definitely need them. The Country Club is also nearby and a very good choice. If you want more casual, there is The Joint (BBQ, excellent). I have heard good things about Bao & Noodle but have not been there.
St. Roch Market is a good choice for casual food if people in your group can’t agree on what they want to eat