The elders’ connection to the prayers would seem to be similar to the connection of the angels in Revelations to the wrath of God that they poured out of their vessels onto the earth. The angels were not the party to whom the wrath of God was directed, but were simply administering it. Likewise it appears that the Elders were not the party to whom the prayers of God’s people were directed, but they were simply administering prayers made to God by His people (e.g. Psalm 58:8b) as part of their spiritual duties before the Heavenly Throne.
I do not believe this passage can be relied on as evidence from the Scriptural record of the validity of prayers to saints.
The Scriptural examples–the cited Psalms are broad invocations for all creation to praise God, not only the heavenly host, but also the non-living creation, like the “sun” and “moon”. These do not serve as grounds for invoking the aid of specific angels or saints.
As for the extra-scriptural sources, we do not have any evidence of prayers to the saints until the 4th century century (or the 3rd century at the earliest). And the records from the Church Fathers do not contain or approvingly reference prayers to Mary or other saints until the 4th century. Methodius is cited in the link, but scholarship indicates that these words regarding Mary are more accurately traced to the 9th century.
Cyprian is cited on the link, but his is simply a request to those present to continue to pray for the Church after their death (as I am quite confident that my brothers and sisters who have departed from this world are faithful to do).
The statements by the fathers and writings preceding Cyprian are likewise not indications of prayers to saints, but additional examples of the largely uncontroversial belief that the departed saints are praying for those of us here on earth. Also, when the context is taken into account, the citation from the Shepherd of Hermas likewise provides no ground for the practice of praying to angels (or saints).
I’m not coming at this from a knee-jerk anti-Roman Catholic standpoint. While I’m Protestant (if we’re going to go around putting labels on ourselves

), I have a high view of Tradition, Sacraments, etc. and I have a great respect for the RC faithfulness to Scripture and Tradition on birth control and other important issues in our day. Have a blessed Christmas season all.