If you are facing two ghosts in the corner that both give ying yang or Qi and you exorcise both on a lucky roll/judicious tao tokens and/or circle of prayer ... can you get teh first ying yang use it and get the second? Or is it one ying yang and one qi or 2 qi?
It's the latter. Exorcisms are simultaneous (except that you apply curses before rewards). You have to apply a YY before or after an exorcism, not in the middle of it.