For extra flair, require groups to enact scenarios for each other as leads off. Keep audience camera nearly eye level to center of groups with elevated seating. Keep audience camera just over heads when all seated at the same level. If no mixer, make sure anchors go through segments without mistakes. Keep roll-in stories to 3 minutes or less.
Anchors deliver stories with no cover shots.
Use cardboard or something, but make it look like a set. Cheap blue cloth looks good. Don't be afraid to tinker and be creative, but put one kid per job if possible. Recommended - Cooperation with another class doing same unit. Groups of 3 - 4, use bells to determine first answered, pit classes against classes.