If Theodora dies Justinian could either lose all hope and bail (she famously convinced him to stay and fight IOTL), or her death motivates to stay and fight out of bloody-minded vengeance.
If Justinian or both die I imagine much would depend on if any of Justinian's generals and relatives (Boraides and Justus?) present in the capital are able to take charge of the situation (in conjunction with Theodora if she's still alive) to try and fight, or try to cut a deal or flee.
If the Justinian dynasty goes completely down in flames the rebels were obviously trying something with Anastasius' nephews, but I doubt Hypatius' position would be all that secure.