1) Master= Madara. NO
Master = Kaguya. He did not betray her. He betrayed a shinobi who he had planned to betray for a very long time. All this time , Madara could not understand BZ. That is Madara's failure. His overconfidence.
2) BZ was not coward. He was like Madara.. Madara used Obito when he required. BZ used Madara. That does not make him a coward. If that is coward, Madara is coward as well.
