Touch of Jacob, Key to Destiny by Cosminus

In the Package Flocke tells Jin that the he needs all of the candidates on the Plane in order to get off the Island. I think that Flocke is planning to leave the Island in the same manner that the Oceanic Six came back in the season 5 episode 316...

Eloise Hawking said that all of them must be present to get back to the Island, that is because when all these conditions are met, right coordinates, presence of a few candidates, a Gateway opens that allows access to the Island.

But this gateway is unstable, in 316 some of the Candidates were sent back 30 years in time instead of arriving in the present Island time line, they ''remedied'' the situation by causing a electromagnetic anomaly at the Swan site.

I think that Flocke is aware of the potential consequences of opening the doorway back and from the Island. He knows that this could result in the destruction of the Island and the time between the 70s when the gateway was last open and when they attempt to leave . Creating a alternative time line also known as the flash sideways.

I believe Jacobs purpose is trying to prevent the candidates from leaving and form t from ever happening, but even if this is true another question lingers: Why does Jacob have so many candidates? The only explanation is that he was only suppose to be Jacob for a temporary period of time, yet MIB killed them before they could replace Jacob. Or even more interestingly maybe the Candidates serve an additional purpose except being possible replacements of Jacob.