The ninjutsu sucking is Obito's personal technique..Though Obito seems to be able to control the tree like extensions of his arms. (kind of thought still the tree should of absorbed Sasukes attack.) He has already replaced Madara so attacking him while he is OP is just silly. He could easily end both shinobi's. Madara I am unsure but I think he was just telling Hashi that having some of the Kyuubi and Hachibi will allow the petals to blossom. He just pointed it out IMO since his eyes can sense and notice so much more than that of Hashi.
Thanks my dude on the Feng notice!