She recognised that she needed a Saviour. "My spirit has rejoiced in God my Saviour," she said. Saviour from what, if she was immaculate and sinless?
He saved Her by preserving Her soul from inheriting the original sin, which means that Her soul remained immaculate and full of God's Grace, and She remained thus of Her own free will.
Exactly, and if God could have done that, He could (and did) do the same with His Son when He took on human flesh.
So, you believe that God was capable of preserving Mary's soul from inheriting the original sin at the moment of Her conception?
As far as I am aware, Scripture doesn't even tell us who Mary's parents were, let alone whether they were just or not.
The living Being Who is our God has spoken about Mary and Her parents. All of His thoughts and words aren't confined between the covers of any one book.