There will be more than 6 people leaving the island...

[Leah Loves LOST]

I really think that not only 6 people get off that island. Whether the people back home will only recognize people from the manifesto as the 6, or whether the Losties decide who they will say are the Oceanic 6 is the question. They may "hide" those who want to stay unnoticed. We see from flashforwards that Ben is back, but wasnt on the plane. Kate probably doesnt count as one cuz shed go to jail. If they put Aaron on the plane, he doesnt really count cuz he was born there and not listed on the manifesto. Desmond was in the drivers seat of the chopper and he wasnt on the plane, so he could hide himself too. I think more than the 6 get home, but they are not all going to turn themselves in to be known as the O6. This would mean that the people who are on the freighter and the chopper either get killed (or theyd tell everyone who they found) or they go back to the island to retrieve more people/find Ben/Jacob.
Sayid working for Ben may mean that people go to the island and either hurt the Losties, so they go home and get revenge, or that the Losties are still out there on the island and people are searching for them, and Ben wants to keep them hidden and safe, so he has Sayid kill those that are getting too close to finding the island and the truth.
Or, I could be wrong...