Of the four, the only one I really like is the first one.
I don't care that they are not smiling. It just isn't a feel good portrait. So what? I get a nice feeling from the sisters. Technically, your PP is very natural looking here. I just wish that the pants (lower right corner) were not so prominent and gray.
#2 Your WB or PP is off. Her hair is green. The lower third of her face is green.
#3 Crop it tighter (above the knees, down to her head, and some on the left) and fix the exposure and it would be very nice.
#4 The older sister has no looking space and I don't like her finger on the should of sister the younger (lower right corner.)
The more I look at that first one, the more I like it. Keep shooting.