In Heaven there are no bodies yet, only souls, right?
How do body-less souls communicate?
With their ears? Their physical brains and mouths? No, they won't have them till after the Resurrection.
Do the saints in Heaven speak to each other, the angels, and the Most Holy Trinity?
So how do souls communicate? From soul to soul by some method that eye has not yet seen and ear has not yet heard.
However, that faculty of the soul was given man at creation, and we have it now here on earth, and shall retain it (obviously) in Heaven.
Personally I think those body-less souls communicate just as our souls here on earth communicate with God, through an act of the will, in a form of prayer.
Where does the ability to pray come from? That too, here and in Heaven, is a gift of God.
In Heaven all those body-less souls participate in the Beatific Vision.
How do they "see" God if they have no bodies?
Its a mystery, but probably much the same way God speaks to our souls, which does not involve physical senses.
Furthermore, only matter, our physical being, exists in space and time.
Those souls in Heaven exist outside space and time. They exist in a timeless Eternity.
So they have FOREVER to "hear" the prayers of the faithful on earth.
And they "hear" them simply because God hears those prayers of the faithful on earth, and the saints are participating in the Beatific Vision.
Yes, its a mystery to us, as scripture says eye has not seen what God has waiting.
The Communion of Saints ain't that difficult to grasp.