Re: Naruto and "Granny" Tsunade
Here's the reason that a potential relation between Naruto and Tsunade is unnecessary.
Motoi said: "In order to ensure that the jinchuuriki wouldn't turn traitor, it's been common since long ago for them to be chosen from among the spouses and siblings of the five kages, or others who are close blood relatives. The strength of the jinchuuriki served to protect the kage, the head of the village, as well as serving as a display of the kage's power"
Tsunade's choice as hokage was done because she was a powerful, legendary ninja and also a student of the Third's - which would allow for the continuation of Hurizen's legacy and continued stability in the village (I think the Third was fairly well liked.) So, not only is she related to the Senju and talented, she was a student along with the man who was the sensei of Minato (Jiraiya), who's son is the jinchuuriki - who was also taught by Jiraiya.
Add that to the fact that it was Jiraiya AND Naruto who convinced Tsunade to take the mantle of Hokage, you have a direct endorsement of Konoha's Jinchuuriki for her to be Hokage. The blood relation is unnecessary.
(Really should have had this argument in earlier - feels a little late to the table already. Oh well.)