Boards only make one direct appointment - that of the CEO. The CEO is responsible for every other appointment although obviously doesn’t make all those appointments his or herself.
That said, if the appointment is for a senior management role, the CEO would take his or her suggestion to the Board for feedback and hopefully ratification.
So if correct process was followed, Rosich would have driven the Bell appointment but the Board would have had input. This theory that the Board has placed Bell into this role to stand up to Rosich is, I think, bunkum.