You are trying to justify praying to the departed....
My source...Gods word. It would give you and those who believe they are communicating to departed saints an education in what Christ warns us of and what the boundaries are we are not to cross. We are not to attempt “Crossing over” those boundaries...but the imagination of ones mind certainly can trick him to believe he has done so...as well as his fantasies.
Use of these men does not justify your stance....they were not praying to departed people...not a one. These men were great men of faith and with special missions. Rather than accept the literature the catholic church uses to promote their beliefs and what they require their members to believe...read the accounts in full of these men in Gods word yourself...and learn why, who, where and with what purpose God elected them. You will find that in their time God did many amazing things to advance the Gospel and His plan for men....we now know what the gospel is..and we know what He expects of us.
As for what Revelations speaks of...this is the future for the most part and not yet in our time...further we have work yet to do for Him... and are called to look for His coming. Not go off into the tangets which shipwreck peoples faith.
There are those that seek that which God has determined not to show us...you tread on dangerous ground when you attempt to go beyond what He has revealed...and dabble in the spiritual realms.
The dead are alive, and they do hear our prayers, and they offer our prayers to God.
“And when he had taken it, the four living creatures and the twenty-four elders fell down before the Lamb. Each one had a harp and they were holding golden bowls full of incense, which are the prayers of God’s people.” — Revelations 5:8
Throughout oh, the entire REST of the BOOK, these same twenty-four elders watch the events on Earth below and offer their own prayers to God.