A spoon works great as a scaler for average size panfish. If you really want to go to town, get yourself a 1×1 about 8 inches long. Then nail three bottle caps to it.
With four year olds, I would stick to filleting and removing all bones although leaving the skin on and scaling adds so much flavor.
Otherwise I’m a “whole” fish person myself. My FW likes the breading all around potato chip taste.