Who attends the ceremonies in The Giver?

The people that attend the ceremonies in The Giver (by Lois Lowry) are first the children. Children are considered to be when they are 1-11 years of age, or an "Eleven" or a "Two" as in the story. There are also newchildren who are with the Nurturers, two other people that attend the ceremonies. The third are the Committee of Elders, (it's members, the head elder, and the receiver). Finally, there are the Laborers (EX: they sweep the hair after the Ceremony of Tens.)

I'm pretty sure I'm missing things, and if I am please edit :)