Hard to find a “happy faced” Ben Linus.
Ben is a “good guy,” in respect to the overall good. Whether Ben is trying to protect the Island, or protect the world FROM the Island, he is working for the good of the future.
Ben didn’t want John to die, Ben wasn’t sure that John had to die. But Ben would have known Jin, in the 70’s, as part of Dharma. As soon as Ben found out that Jin was alive, on the Island, some pieces of the puzzle feel into place in his head, and he had to “kill” John.
Considering the comings and goings to the Island in the past, Ben would have to have know Mrs. Hawking. Hearing John mention her name did not trigger Ben to kill John, but it told Ben that Widmore had his fingers in the pie again. Ben knew that the only way that John could have know about Mrs. Hawking and her location in LA., would have been through Widmore.
And why didn’t Widmore just go to Hawking in the past to find the Island location. well, first off, I don’t think they are on speaking terms anymore. I believe they were married and the parents of Faraday. Other wise, there would be no need for him to have gone through all the trouble with the freighter and the mecernaries and the science team. No, Hawking is not on Widmore’s side.
If anything, the greater good for Ben would be to eliminate Widmore’s “spy,” who in this case was technically John. This accomplished two things. thwarting Widmore’s plan, and fulfilling the what Alpert told John, that he must die.
For what ever reason, Ben, Widmore, Hawking, Faraday seem to know the “rules,” but they don’t always believe that the “rules” are immobile. What ever their ultimate purpose is, they feel that they have some control over it. And everyone else are pieces on the game board.