I am still wondering if Madara will actually need both halves of the Kyuubi to complete the Juubi. One would think that with some of the Kyuubi still trapped in the dead demon seal, the Juubi would not be complete. I have a feeling that Madara is aware of this and actually has some method in mind to remove it. We have already seen multiple techniques that seem to involve bringing souls back from the dead. With the Rinnegan and the Eternal Mangekyou it would not surprise me if he now has a way to reclaim the Kyuubi's other half.
Right now Madara's plan still seems to have some holes. One of them being that the 9-tails is partly sealed. It seems strange that Madara is choosing to go after the 9-tails when he does not yet have the 8-tails. I highly doubt that this is being done without a very specific purpose. There is also the problem of the Jyubi's body being tapped in the moon, does he intend to destroy the moon and create a knew one, or does he have some other method to retrieve it. That also is difficult to determine, it will be interesting to see what Madara is now capable of and how he uses the Rinnegan.