STL - Rehersal Dinner Restaurants?
Here are some rambling suggestions:
Frazer's on Pestalozzi has an upstairs banquet room; do not know how many it holds.
Also, I wonder if the folks at Sage will block out their upstairs dining room for you.
And the Ninth Street Abbey is a possibility
How about the back room at Lucas Park Grill
Fun, casual: the Atomic Cowboy on Manchester.
Can you get a downtown restaurant that is only open at lunchtime, such as Smitty's (which is fun and casual), to stay open at night for you?
The Tap Room