They stand a chance against Madara easily, I can see 4 of them going up against Madara quite easily. The fact their all Edo's as well is probably all in their favour as well.
The Juubi, well that's a little different. You saw what it did before the Hokage's came, this barrier they have put up will only hold him for a little bit and once it's in it's new form well...yeah good luck. I think Naruto will be the only one who can defeat him, we saw what the Juubi sensed/saw within him. I think it see's Naruto as the biggest threat at this point in time.
Once he gains the other half of Kurama's chakra plus some eight tails (dunno how this will happen or whether it will be a portion of it but I can see it happening) then I can see something happening within Naruto, maybe seeing the SO6P or something like that.