It makes it appear that Hashirama is just too powerful to be controlled by that jutsu, even when someone has his cells and is as powerful as Orochimaru. I would venture to say that Kabuto would have the same trouble with Hashirama as well.
He can control hashirama like he did in part one his mistake is tht he gave them their personalities so yes hashi would know how to break jutsu (if Madara knows we can venture hashi knows as well) not to mention hashirama is stronger then his brother
And everybody was confused on why hashi was acting so care free kind of through them off my guess is while he was doing tht hashi summoned enough power to counter oro control
But hashirama isn't out of the Edo tensi just yet oro always has something up his sleeve and is strong as hell know tht his arms have returned to him not to mention even though hashirama has summoned enough energy to counter oro
I believe of oro wanted to he could just shut down their personalities similar to what kabuto did to zabuza or troll kage (at end)
Its simple because in order 4 orochimaru's ET 2 become strong he needs just cells of the first hokage. how are u going 2 control the person from which u get ur power from