Nice work! I especially like #s 3 and 4 as the inclusion of the ball gives a sense of purpose to the image. Good work with the DoF and selective focus in isolating the subect from the background. My one suggestion though would be to consider spot-metering as the faces and fronts of the children are rather dark. This type of work is always give and take as you don't have the luxury of using supplemental lighting or asking for 'do-overs'. Brighter faces and shirts would have resulted in some more blown areas, but I I think the overall result would have been stronger images.