Ok sooo Mito Izumaki is Hashirama senju's wife and most likely Tsunade's Grandma.... is it possible that Tsunade learned Fuuinjutsu from Mito, and may be planing to use it and possibly other techniques to defeat and seal Madara?
I havn't bothered reading other peoples post but I think its possible, and I think tsunade might be the key to beating madara - you never known. She has shown skill in sealing techniques - her seal on her forehead. Its S-rank (I think), and rank is to do with the difficulty of a technique. But in her case, it might be S-rank do you the great risks (genesis rebirth).
1) Madara thinks she is just a senju for now... however, he does not know that she has some uzumaki heritage.
2) When she said "My power has been passed down through generations..." She hinted it is about sealing techniques.... if i remember correctly, the uzumaki clan passed their sealing techniques on to the next generation before they died during a flashback.