Cake is boring. Unless you spend oodles of money, when they serve it to your guests, it's usually dry, or bland, or has too much sugar.
We did ice cream sandwiches. Diddy Riese doesn't ship, but if you live near LA, they're delicious and inexpensive. 3 for $1, regularly, and less if you buy in bulk. Lots of varieties. Our venue supplied the ice cream, and one of our bar tenders scooped. We had toppings and it was delicious.
The cookies will stay fresh on their own for a few days, but you can freeze them and they taste just as good when they thaw.