I agree...any of those sets of legs could be of a 16 year old.

I think some of those set of legs are of the 2 kids that will be in next week's episode (after seeing still shots with Ana-Lucia & Mr. Eko with them). One of the kids is holding the teddy bear on the beach after the crash and so it would seem likely that that last pair of legs is one of the tail-end kids. (Unless of course, they're just messing with us again!!)