I think the folks from Dharma are still around. The people from the DI that were on the island were killed by Ben but there were more of them off the island. Who dropped that food supply? Once their people on the island were dead, the DI had to find their way back to the island the same as everyone else. "What lies in the shadow of the statue?" is a code much like Desmonds "what did one snowman say to the other snowman?". It is a way to tell if someone is a part of the DI. Whatever the other survivors have in the case, I believe, is a way for them to take control of the island and maybe help the rest of their people find it. I think they "found" guns because they knew where they were.