“I cannot understand how asking Mary or the saints to pray for us is so terrible. They are already in heaven.”
Are those who are in heaven, other than the Trinity and the angels, aware of what is going on in this world?
Why sure, we are surrounded by a great cloud of witnesses:
Heb: 12:1
“Are those who are in heaven, other than the Trinity and the angels, aware of what is going on in this world?”
Only in the West would that question be asked. In the East it is understood that there is a constant “back and forth” of angels and saints and the Theotokos between earth and heaven. We “see” our patron saints with the “nous”, the eye of the soul and they are very real. Although mass visions like the appearance of the Theotokos over a church in Egypt are a matter of wonder, that a regular Christian would see her or saints while saying daily prayers or at the Divine Liturgy is not all that remarkable. We expect to see them...and we have no doubt that they intercede for us just as much as we intercede for each other.
You wrote:
“Are those who are in heaven, other than the Trinity and the angels, aware of what is going on in this world?”
Sure. I think they rejoice over conversions as implied in Luke 15:7-10 and they seek the justice on earth as alluded to in Rev. 6:10.
And if they are not aware then I think Rev. 5:8 makes no sense.