I think Romana could still be traveling and trapped in E space. Though E space is small compared to our space, she had alot of work to do. Besides, with the destruction of the Gate, I don't know if she could leave E space. If she is stuck in E space, it is logical that the Doctor could not sense or feel her exsistance.
As for Rassilon, the Timelords, in desparation must have ressurected him from his tomb. (as in Five Doctors) We know he was the most powerfull Timelord. Also, in "The Five Doctors", Troughton tells the Brigader that no one knew the exent of Rassilon's powers or if he was really dead. Once alive, a vote would be unnecessary. Who would challenge him?
