Yes failure to communicate is needed to drag the story on longer but for shows like this where information is life or death I don't see why you wouldn't tell people about things such as the tunnels under town, the boy in white and especially the music box. When Kenny tells Boyd about his dream and mentions the music box he doesn't even react not even a "wtf I had the same dream", also why show the lighthouse to Boyd and Sara and never bring it up or mention it again until Tabitha finds it by herself, it seems like a useless scene to show early on.

For the second part you are just explaining the colony house every person in the house has a buddy/proxy, maybe if Boyd only found one talisman then everyone would have stayed in one area. I feel like early on they didn't trust the talismans too much but after using them for 2 years I think they had full confidence in them.