If you're not already doing one with the wedding, I think a dessert party is a great idea. You can do appetizers with the desserts if you'd like. They will only serve food for an hour without additional charge, but I believe you can have the space for longer at no extra charge if you want more time to mingle. I would do 2 hours for me instead of the 90 minutes they normally do. I'd start at 8, food from 8:30 to 9:30 and then finish at 10.