When I hear talk of slightly formal celebrations I always think of the Corner Kitchen. It is perfect for this type of thing. And in my oninion an A recommendation. I had my bridal brunch there a few years back. They were very accommodating and had everything ready on time. We didn't have a separate room but had our own space upstairs away from the crowds. It's an adorable house and the food is so good!
It is one of those places where you realize why you live in NC. It is just that friendly and they really go out of their way to make sure your experience is perfect.