I get so caught up in this now I am even replying to myself. I read your link and it wasn't apparent to me what they feasibly could have done to secure fresh water. After they used up whatever they had brought in the plane, and maybe lapped up some water from tree roots, what then? I think they could have started a fire, probably one or both of them smoked, but what good is that? It seems like water was a big issue for the NC survivors, couldn't they have accessed pots or pans from their ship to distill water? The water tank they found (I think) they didn't utilize for whatever reason. Even if it was sound, would the rainfall on Niku surpass the evaporation rate so that there would be any water in the tank except maybe a layer of wet mud on the bottom?
I looked up Captain Manning, saw that he was exactly the man for the job, not Noonan, and he was "trained in survival techniques". Maybe for shipwreck survivors washed up on desert island? Did he ever comment after their loss on what he thought? That would be very interesting to hear, but probably he kept his mouth shut. I suppose criticizing Amelia would be like criticizing Mom and apple pie at the time.