Note, I was raised Roman Catholic, so hear me out:

If Mary were born without original sin, she could have fulfilled Jesus' mission for him. She would have no corrupted moral faculties, which means the natural ability to perfectly self sacrifice for the good of another.

She would have INSISTED, especially as a mother -- "NO, I will go to the cross for you". What mother doesn't want to spare her son's life by putting herself in the stead of danger? Especially knowing he's completely innocent of all accusations? Did this happen? Did she attempt?

The Gospels highlight Mary's faith not her sinless-ness, because like all children of God her faith was mixed with doubts. She doubted Jesus at times. She questioned whether he took this whole "Son of God" thing too far. Remember, having a close physical proximity to God the Son in the flesh does not guarantee sinlessness or perfect faith. His own brothers and sisters and neighbors from his childhood doubted and even became contemptuous of him.

As far as speaking with her... all souls who have departed in the faith are "asleep". Have you ever had a conversation with someone in a deep sleep? In Revelation the martyrs in the presence of God raise up their voices and cry out "How long, O Lord?" And God essentially responds, "Go back to sleep, it is not time yet." Meanwhile, Christ Jesus we are told is an advocate for us, before God's throne, always making intercession for his people. This is also somewhat prefigured in the garden of Gethsemane, when his closest most faithful disciples continually fell asleep on watch despite the urgency of the night, but Jesus remained perfectly alert and in effectual prayer for all of us.

As the Psalmist prayed, "Whom have I in heaven but thee?" in context of praying for supplication and deliverance, God alone has the ear to hear and the mighty right arm of salvation. Amen and amen!