5. No it doesn't explicitly say... From your mangapanda source (which could of been mistranslated) stated " Nagato is of Senju lineage" which could be viewed differently. You said they share a common ancestor but what does lineage mean?
Really? There is no other way to view it. Nagato=Senju and using mistranslated as an excuse to grab at straws is not logical at all. Cmon cuh.