Well to me an interesting image if it isn't just a straight portrait is one that invites your eye to move around within it. I think the girl draws attention because she is in focus but the colorful shirt invites the eye to explore other parts of the image as well. My thought anyway.
Agreed, and the fact that the boy is looking in a different direction to everyone else adds a question to the viewer - what has he seen?
There is, however, quite a lot of bright colour in the background - so perhaps a bit of selective desaturation might work to help you control how the viewer was drawn though the image - one where the eye has a distinct 'path' generally works better than one where your viewpoint jumps about from place to place.