“Saints are alive in heaven.”
Of course.
“We ask them to pray for us.”
Of course you do.
The better question is...
Do they hear?
and
Do they have any power that a Christian does not have already to BOLDLY approach the Throne of God?
The answer to the first is, we have no idea.
The answer to the second is, they do not.
If this is a doctrine from God, He would have either commanded it of His Church or shown it during the first 100 years of the Church. Neither is evident in scripture.
So pray away. You’ll never know if you are heard and you could have been talking directly to the Father.
**Do they hear?**
The pass our requests on to the Lord.
They would not even be Saints if requests had not been granted by God.
Did you read the Scripture above?
You seem to be making an exception for “departed” that does not exist in scripture. We are to ask for other’s prayers, not excluding anyone in the Body of Christ.
As to the Saints in Heaven being aware we have scripture from Revelation and that concerning the “cloud of witnesses” to tell us they do - as well as being alive in Christ, God of the living.