We also had mini ice cream cones, mini cupcakes, mini bagel pizzas and I blew up more water balloons and strung them up so we had mini decorations as well:
We played a fish game where I laid an old shower curtain that had fishes all over in the design over our dining room table and all the kids hid under it and I was the blind shark reaching under the table and grabbing little fish. If I guessed who it was without looking and I was right they became a shark with me. It wasn't mini themed but the kids had a blast with it. We also kept the time "mini" just and hour and a half because we invited 15 kids including our 3 -- We usually don't have that many but it worked out and I really enjoyed it.