Now using the list above... I wonder who these two are.
ENHANCE!
My first thought is that they were Neytiri's children but as the male Na'vi on the right looks younger and Tuk is Ney's youngest child I think they must be Metkayina folk. Also the garbs they're wearing look new and it's almost as if they're wearing face paint on their forehead, points towards being from a new tribe.
Reya on the left. "She is described as "graceful and strong" and "the young Neytiri of the ocean"
Aonung on the right. As he's the child of the head of the clan.