Sigh...
I really can't comprehend how this thread began with a Madara + Hashirama vs Akatsuki to Madara vs Hashirama with the Akatsuki out the equation.
Must I really?
Lets break this down so it isn't Madara + Hashirama.
Madara only against Obito:
Madara has the ability within him to control him; Obito can't attempt to block Madara as there isn't a bijuu nearby he can fuse with.
The rest:
If the main man Obito is under Madara's command, then they're rest are dust.
"Ohhhh Chibaku Tensei GG", for those who will post that, then you're completely and utterly stupid. I'm not even going to lower myself to you to even explain as to how that can be easily countered.
Hashirama vs Obito:
According to the manga, Hashirama cannot defeat MS Obito. Hashirama lacks reflexes such as Minato's, and every single attack from Hashirama is almost negated by Obito turning himself Intangible. The only chance Hashirama has by creating that forest that puts victims to sleep; even then he could hold his breathe (if he isn't panting or exhausted - which is extremely unlikely as he was able to control 7 bijuus, gedo and use MS without even breaking a sweat).
The rest:
If Hashirama can barely handle Obito, then adding the likes of Nagato and Itachi to this is just an overkill; thus why it was Madara + Hashirama to begin with, Madara being his back up and vice versa.