Daniel looks like an unwilling participant. It seems that he is there against his will. He will probably be the source of some of season 4 answers and mysteries. Miles is a ghost whisperer who can communicate with the spirits. It suggest that the future knows about the island spirit and the crash victims. The pilot is probably the "Ben" of the group. He knows more than we think he does. The last of the four is there to figure out where exactly they are located. She is an archeologist so she will be looking for physical clues.