3 yr old party at 3pm. Do I have to do food other than cake and ice cream?

I thought I was all done. But yesterday my DH asked what else I was serving?? I think at 3 in the afternoon it should be obvious to the parents/adult family that I'm not planning to feed them a meal and I shouldn't have to shell out money and time with a big snack fest. My DS isn't used to having a huge snack in the afternoon and probably won't even finish his cake. It will be adults, 3 young cousins and 1 friend from school. What do you think?

I would not have extra food for a 3pm party. Too much and they will not want to eat dinner.