Why do the Itsuwaribito exiled to Nadeshiko Island have guns and forged weapons? It seems unlikely that they could get them/make them there. On a related note, did they have children? Where else would the children come from (what would they be exiled for)?
Utsuho has shown remarkable physical strength in fighting off people before. Why is it so difficult for him to pull some small fallen trees off of Pochi?
How did the hard-core criminals not notice the village inside the massive rock on Nadeshiko Island? It is clearly open from above (because crops grow) and it makes little sense that nobody would have thought to climb it.