I don't know if you've already discussed about this, so I apologize. So I was thinking that like everyone thinks that this people who chased them was at the time of season six. As we know, according to Ajira's bottle its around 2007+ year. But what if this they were in far future...My opinion is that these people were someone that Hurley and Ben brought up to the island, for replacing him as a guardian of the island. And I know there were Ajira bottles over there but that doesn't mean that some of its passengers is. Or maybe it was Hurley, Ben and Desmond?
I know its a shit theory, but I found it interesting.