The answer
To answer some of your points, God chooses to reveal to St. Mary or any other saint whatever He wants to reveal, and remember that departed saints are no longer restricted to the body; therefore, they can acquire more abilities while in this new state of freedom from their mortal bodies. Praying and asking the intercession of the saints has nothing to do with mediums and soothsayers. When praying to the saints, one does not expect to know the future or foretell events; one is asking the saints to pray for us before the Lord.For more reading please check:
www.suscopts.org/messages/lectures/misclecture6.pdf.
www.suscopts.org/messages/lectures/marilecture2.pdf.
Denying intercession of the saints is primarily a protestant and not an orthodox teaching.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)