You are working with a family that has nicknames for all the members. Mother is called Mimi and Father is called Papa. The children are called Bubby and Sissy. After introductions, you would:
1) call the children Bubby and Sissy and refer to the caregivers as Mother and Dad
2) address the caregivers as Mimi and Papa and the children as Bubby and Sissy
3) ask each family member what he or she would prefer to be called
4) call the children Miss and Mr. and the caregivers Mr. and Mrs.