BBM - LE would not give the names of the children, if identified, to the parents. They (the boys) would have no bearing on the case (Dylan) at all. If it was mistaken identification by the postal worker, can you imagine the hounding that these children would get from media and family and strangers?
What I find odd, and it just came to me today. You have a postal worker that delivers in the area, perhaps for years. They tend to get to know the people on their route (heck I talk to mine all the time at work and it's been years) I'm sure the turnover of postal workers isn't that spectacular in that area so they would tend to learn who is who around there.
She knows, believes, suspects, that she saw Mark's son Dylan and another boy walking.
How is it that Dylan is easily remembered, almost specifically, but nothing about the other boy? Why wasn't it I saw Mark's son and that Masterson boy (just making the name up) walking down the road.
It's always been two boys and one looked like Mark's son Dylan.
I'm also certain that if she did tell LE who the other boy was, they were all over that kid as soon as possible.
All IMO and imagination