Nice shots, but, here's some critique. I definitely think 5 is the winner here.
1. I think this was softened a bit much, and then his left hand looks a bit odd just being there.
2. I think this shot was wayy over sharpened. You can see it in his eyes, his chin, and his hair. Especially when seen with the other shots around it I would back off on the sharpening here (and maybe have fixed the hair a tad

) Cute expression, although his foot at the end looks funny being half cropped off.
3. cute expression, maybe a few areas are blown out, but I do like this photos. As others have said a bit more face or a bit less face would have been nice. I am not a huge fan of just the very top of the head getting chopped off. My personal preference is chopping at the foreheadish or having the whole head.
4. very cure shot. Again, it would be nice to have all the hair, or less of it. also, the foot in the background is very distracting. I Love the expression though.
5. great capture, this is more of where I meant was the other good place to crop heads. I like the sharpness of the eyes. a crit is probably the blown spots on her cheek. Also, her hair is distracting over her right eye.
One other comment is that the whitebalance seems to change with the different shots here. Some are more red and some are more yellow (at least that's what it looks like to me).