Hi Vox :) I think the meaning of these dreams are going to depend, in part, on your religious beliefs and how much of a focus they are in your life. Since I don't know that information, I'm going to say that the exorcism dream is about you wanting to remove a part of yourself. It's most likely some part of yourself that you see as wrong or bad.
My experience has shown is that it is better to try to acknowledge and integrate parts of ourselves that we don't like or judge harshly, rather than do away with them, because excluding parts of the self can cause psychological difficulties. Look at the aspect you see as bad and consider the flip side - what is the positive benefit of this characteristic?
I think the crosses dream has spiritual significance because the associated feelings were positive, but I don't know in what sense. Maybe it's simply a reflection or acknowledgement of your awe of Christ, of Christ within you, or your connection to your spiritual nature.
To connect with the dream symbol, find a little bit of quiet space, close your eyes and call up the dream image in your mind. What words or emotions immediately come to mind? Whatever the words or emotions - they are describing where you are spiritually right now.