Jack and Sun meet Eloise Hawking, Desmond meets her again

When Ben, Jack and Sun arrive at the church where Eloise Hawking is, Ben gives Sun Jin's wedding ring. She tells him that Locke gave it to her when he was alive. Ben clarifies to Jack that Locke didn't come to him but he went to Locke. Sun agrees to go back to the island with Jack and Ben. That's when Desmond walks up and asks if they're here to see Daniel's mother too? Ben seems surprised that Eloise is Daniel's mother. Either that or he is surprised that Desmond knows this. They all proceed into the church and Desmond seems to immediately recognize Ms. Hawking. In case you forgot, Desmond encountered her in his time shifting after the Swan Station imploded in "The Constant" in season 3. Eloise says to Ben "I though I said all of them" but he replies "this is all I could get on short notice." She say "Well, I suppose it will have to do for now." The episode ends after she says "Alright, let's get started."

It seems that Locke did not approach Sun like he did the others who are off of the island. It would seem that he and Ben may have worked something out in advance to convince Sun to join the cause. Does Ben not know that Eloise Hawking is Daniel's mother? Why is Eloise Hawking not seem all that concerned that all of the six are not currently there? She seemed pretty adamant that all of them be there when she and Ben spoke earlier.