The first one is charming (a little nit pick would have been to put down the toy).
Wonderful smiles! Not sure about the flare? lower right in #2.With the girls I'd double check the hair/bangs, as they move around so can the hair, especially backlit it makes the flyaway strands more noticeable. Check the clothes too for bunching/wrinkling.
Great portraits of your kids! Since you asked for critique, I would suggest moving them slightly into the shade, that way the back light from the sun isn't as strong and doesn't blow out around them.