None of the Kage have completely broken free of Orochimaru's control. Tobirama was about to go join the war, but Orochimaru stopped him. In that same chapter, Hashirama was able to freely control his body. Orochimaru indicated that he could still control him by exerting more energy into his technique, though.
Compared to when they were originally resurrected in Part 1, Tobirama and Hashirama are considerably more powerful (probably more comparable to when they were alive). This makes them harder to control. Plus Orochimaru has to control two other Hokage at the same time. If Hashirama wanted to turn on Orochimaru or Sasuke, he probably could. Hashirama could probably break Orochimaru's control over the other Hokage, too. However, Orochimaru can still release the jutsu.