well we know for sure from the bible, that God sits at a throne, with Christ on his right hand. We know from Stephen’s soliliquy that Christ sometimes stands at the right hand of God. We know there are 24 elders seated and a great host of others. We have no indication however that Mary sits over all of them, at the left or in the middle.
Aside from what is told us in Scripture by John, there is NOTHING in the Bible that supports the Catholic arrangement of heaven or hierarchy of saints.