Peace-be-with-you:

You stated the saints who are in heaven can pray for us. I believe they can and do pray for the church as we see in Rev.6:9-11; Now note they are asking concerning what they already know, the persecution the church is suffering under. In Lk.16 the rich man asks on behalf of his brothers who are still alive. But they ask because of what they know not because anyone has asked them to pray for them. Our intercessor is Christ, this is the one we pray to and no one else. 1Tim.2:5;

Many do petition the saints to pray for them, but there is no scripture that tells us to do so. We are only to pray to God as we see in Rev.22:8,9 John worshiping the angel is informed by the angel that he is only a fellow worker, not to be worshiped, he has no authority except that given to him from God.
Likewise Peter refuses worship from Cornelius in Ac.10:25,26; Peter states he is just a man.

We are to pray to the one who can speak to the Father on our behalf, Christ and Christ only. Col.3:17; To pray to saints is to believe God honors one man above another and that is not true. To think God would listen to Bill instead of me shows God is partial. God shows no partiality Ac.10:34; Rom.2:11; Gal.2;6; Eph.6:9;

The dead are with Christ and praying for the church, not knowing anything that is happening on earth, they are waiting for the judgment day when all will be known and we shall spend eternity with Christ. So to pray to the saints is not only folly but a waste of time for they cannot hear.

RJ Mac