Should children be screened for pre-diabetes?

Depends. Universal screening of children for diabetes is not recommended, but certain groups my benefit from screening, including those with a strong family history of diabetes and children who are overweight.
Depends. Depends on their history and growth. For a child with normal growth no symptoms, and no family history screening for type one diabetes is low yield. For type two we usually screen for children that are overweight, have a family history or any concern about increased urination or thirst.
Yes, for type 2 , If, their parents have type 2 diabetes, and child overweight for type 1 if either of their parents have type 1 diabetes.