I think you're also being a little free with what you term protestant theology. You consider yourself the arbiter of what is protestant theology? Luther, Calvin and Zwingli are usually considered protestants and they disagree with you. Do you consider them Catholics?
Where did you dream that one up?
You obviously haven't been following many of the Calvin threads.
"Full of Grace" proves Mary was free from Original Sin? If that's all you got biblically, you are still on purely conjectural ground.