First and immediate thought:
"I don't understand what I see in the second photo, but it somehow makes me feel sick".
Sorry.
I really don't know what it is. It looks frightfully sweet to me though, hence my strong reaction.
In the first I do miss the little girl's legs.
I am an absolute amateur, so don't necessarily go by my words, but I feel that if you go for more than just a face and shoulder portrait, the limit do go down and take in only half the persons body should be the waist. After that (only my feeling, I would like to stress again!) you should take whole-body photos. And if you do so with children, you should not do so from above, I think.
This is not to say that you did all wrong here. Her expression is so nice and her eyes speak a lot. But that thing next to her head distracts and bothers me.
But it seems like you are around this girl every day (she has so far been in more than one of your photos, right, she is also the one who had the lollipop/*insert American equivalent here which simply refuses to spring to mind, dang!*, right?), so I am sure you will get ample chance to capture her wonderfully mobile and very pretty little face more often.
In the last I like the boy's eyes that convey how well he is focussed on his task, but the crop is so very tight ... I would really want to SEE what he is focussing on. His hand holds it, it is very near, and yet outside the frame that you chose... plus the hand is very large. His eyes are big, they still stand the competition well, but... is there a larger original?