The one shot at ISO 640 is overexposed and a tad blue. The light is flat, as if it was a cloudy day or you were in the shade of the house. Pop the contrast up a little. A little sharpening might help.
The second is underexposed. Fix this and adjust the levels slider to cut off unused tones on the white end. Sharpen a bit and add a bit of contrast. This one is also slanted. Some people don't mind. But I always have an image in my mind of the subjects sliding off the side.
Lastly, for both, people want to see faces. Cut off their legs.
It used to be that it was a bad idea to post modified versions of shots unless the poster had a note that image editing was okay. There were some heated comments made when people ignored it. Accordingly, I didn't post my idea of how they could be improved.
In the third one, it looks like you needed to engage in crowd wrangling. Somebody camera left was attracting your subjects' attention. So three of them weren't looking at the camera. A well-meaning parent, perhaps. Or someone brandishing a smartphone. But they didn't do you any favors. In situations like this, I tell the subjects to look at the smartphone and then that it's my turn.