We are still enjoying this idea, so we had ourselves another muffin tin Monday.
Faith's theme (which she had to guess) was the number 6, because she is 6 years old:
6 strawberry shaped sandwiches of turkey, cheese & cream cheese
6 carrot sticks in ranch dip
6 animal crackers
6 chunks of cheese
Ben's theme, thus, was the number 3, because he's 3:
3 boat shaped sandwiches
3 animal crackers
3 pieces of cheese
and a melon pudding, because I ran out of 3 ideas.