THE ISLAND GAME! CANDIDATES REALLY CANDIDATES?

I was thinking the other day about the past few shows, how amazing they have been and soo on. it then occured to me that the boy in the jungle that MIB and sawyer seen said some words that seemed familier, ‘you carnt kill him’ MIB genuinly seemed angered. but it also seems that a few seasons back when whitmoores goons came to the island and shot bens daughter, he exclaimed that the rules had been changed!

Also it would seem that if these candidates are to replace jacob then he new he was going to die? but surely if he new this he would have changed things? if he went to all this trouble to bring the candidates to the island as part of an illaberate plan then surely when flocke came knocking he simply was somewhere else. but what if these candidates are candidates to kill MIB they dont know it but they are, this leads me back to sayid who was trusted to kill MIB with the sword but he was dark inside and no longer a candidate!

thoughts suggestions ?