Back in the 50's Widmore seemed to have a standing order to kill anyone that came to the island, was that just him? or was that from Jacob?
ben also killed everyone that came to the island, he told Ethan and goodwin to "make" lists...he then picked who he wanted to keep, there is no evidence that jacob wanted cyndie or the kids at this time...or anyone elese for that matter...so I'm assuming that the standing order is still to kill anyone that comes to the island...where ever that came from.
So if the jack and the others are candidates for jacobs position...does that mean they should have been told to the Others that they were welcome, dont kill them...NO!
Its all about faith and destiny...so if they made it past all the others, then maybe they are qualified candidates..of course now WE know about the list of jacob...and so do some of our Losties, but does that mean they know now that they are special..well barely...remember they dont see what all we see...and know...
So basically jacob has his group of followers/protectors, but he doesnt tell tehm he is bringing people to the island....which is understandable, he cant let MiB know who is a candidate and who isnt and what their purpose is....