Here are many links about the crèche or Nativity scene:
These Nativity scenes can be as simple as made of paper, clay, ceramic and range from small to large. The most beautiful set I ever saw had life-size porcelain figures and came from South America. In my ceramic set are:
the Holy Family: the infant Jesus or the Messiah, Mary the mother and Joseph the father, the 3 Wise Men (Melchor, Gaspar, Baltizar), a shepherd boy, an old woman and some animals: cow, camel, sh eep, ass/doney, as well as an angel suspended over the wooden structure, representing the inn.
As for what is eaten on Christmas Eve, that can depend upon the culture or ethnicity of the family.
Her are various links on that topic:
Either crib or creche is correct.
Some of the figures in the creche are Joseph, Mary, the infant Jesus, the wisemen, and the shepherds. Most creches also have a few sheep.
Christmas Eve for most families is not a time of feasting. That is on Christmas Day, when we have ham or turkey, and pumpkin, mince, or other pies for dessert.
However, because Americans come from such a variety of cultures, we have many different traditions for Christmas Eve. Some have potluck buffets, others follow more traditional customs. Check this site.