Nice job on a difficult hot and sunny morning ...
Notice however that they have real trouble keeping their eyes open. Beach shots in Chicago should be PM despite the kid problem. To be AM they would have to be done at 6:00 am. Curt and Holly did a great job of posing this too. There is fairly even spacing between the people. They all are visually touching but not cramped on top of each other. The kid on his dad's lap could be a little to the right to make it perfect!
There is a nice foreground leaf on the right, subject as people, backgrownd as lake and infinity as horizon. Timing though! Even with the overcast the kids couldn't keep their eyes open.
Composition & Diffusion
On the left, the girl on the left is too much directly under her dad ... if he could go slightly left it would make it look nicer ... or perhaps putting the left girl more in front of her mom's knees would also have done that while covering her a little more. On the right I would have liked to make the girl on the right taller ... perhaps we could have switched the girls to make the sizes work better. As it is there is too much space between the right girl and her dad.
The diffuser worked on the left group at 3/4 pose at F16 ... on the pastel background. You cannot use it on full length however or on the white background (unless you have a very specific reason on white)
Composition and fill lights
The top is nice with foreground flowers, subject, background house and infinity into the windows ... They are a little tight together and could the girl on the left have been turned more into the group to make her appear thinner? She looks pretty straight on. On the right they look nice but perhaps a little straight on again ... it is often hard with kids though as their bodies sometimes only go certain ways and won't bend the way we want to make our composition work.
Fill light ... these guys have pretty heavy circles under their eyes. As a rule we want the fill outside to be 1/2 stop under the main. Take your ambient reading (f 8 @ 30th) ... then get your flash to f 5.6 1/2 @ 500th ... then set your camera to f 8 @ 30th. This was also a very much direct overhead lighting situation which exasperated their eye circles ... perhaps the fill could have even bumped up a bit without overtaking the shot?
Happy Shooting!