Well, Michele, now I am somewhat hesitant to post a critique on this. With it being a commission, your client might read this, and all in all it is not a bad painting. And if it was by a lesser artist than yourself, I would consider it to be very good. Although it is not the most dynamic of compositions it is pleasant and a good piece.
But since you asked, I suppose I could give my opinion.
Now I feel that the pose and composition are the issues here more than any inaccuracies. In a thread about three-in-one group portraits
http://forum.portraitartist.com/show...&threadid=410, I touched on this some. I feel that an image of two is harder than of three, because it is easier to get interesting dynamic compositions with three areas of interest than with two.
I think I might have turned the girl's body to her left some so her legs and hands would be below the boy. And so her shoulders would be at a 3/4 angle to the viewer. This would make her hands and the flowers the third area of interest after the two faces. Then turn the boy's body slightly to his right so he appears to have some interaction with the girl and has only just turned to meet the eyes of the viewer.
I did a quick thumbnail sketch that I hope can give a idea of what I mean. But all in all your painting is not bad. I myself would be happy to put my name on it.