At the end of the movie, it is established that Bane would die for Talia, and that she is dedicated to completing Ra's Al Ghul's plan to destroy Gotham. It seems that Bane takes point as "Gotham's reckoning" to hide Talia's involvement and true identity. He seems to listen to her, and she takes control to finish the job at the end (the other members of the League seem to recognize her authority). She is also the one that has the detonator; so, she seems to be controlling this plan overall. She seems to be the hidden hand that controls the plan, and that she was the one that wanted to complete Gotham's destruction for her father. So, is Bane just following the orders of the child he is dedicated to protecting? Or, did Bane really plan everything, and Talia is just there to be a part of her father's original plan?
The fact that she has the detonator pretty much implies that she is the one in charge (you in fact have pointed out the major key facts in your question supporting that theory). if you look at the issue Bane has nothing what so ever to do with Gotham or its reckoning he was even kicked out of the league. But for Talia it was more personal she knew Batman was responsible for her father's death and the reason to avenge him by completing Ra's Al ghul's plan in front of Batman by bringing Gotham to an end.
Bane was merely very loyal to Talia and was very much wiling to die for her plan. Her role in the plan was as much as important as Bane's was to get the confidence of Bruce wayne and Lucius Fox to get to know as much as possible about the Reactor while Bane was responsible for all the muscle work in bludgeoning Batman and Gotham to submission.
There's also one bit which should answer this question. When Talia pulls the knife out of Batman and is about to walk away with the detonator, she plainly tells Bane to hold him until the explosion goes off 'so he can feel the heat.' Bane, being someone who has no qualms about snapping someone's neck, would not have taken that order so willingly unless he was, indeed working for her.