I recall reading in Fr. John Romanides' "Orthodox Dogmatic Theology," that those who died prior to the Resurrection were in a state of partial bliss or partial damnation, just as we are after our death. They *additionally* were held captive by death and Hades prior to Christ's Resurrection.
In no way have I ever understood Orthodoxy to teach that the Righteous of the Old Testament were in a state of torment prior to Christ's Resurrection. Even though Christ's words were a parable, the story about Abraham should make that clear, since I have a hard time thinking that Christ would use that as a merely allegorical example that had no basis in reality.
There was a sudden and fundamental change in their state/plalce after Christ's descent into Hades to break the bonds of death.
They and all who have died since the Resurrection are now alike in an intermediate state of partial bliss or damnation (a state that the Church does not define or try to pry deeply into explaining beyond the limited revelation we have received) -- the fullness of our final state cannot be arrived at until after the general resurrection, when soul and body are reunited. We are not in our full state of humanity unless our soul and body are united.
The state of Elijah would be different from that of the souls in Hades, since he did not die, and did not undergo separation from the body. These things are Mysteries.
I would think that neither conceiving of Hades as a state of existence nor as a specific place is capable of fully encompassing the reality, just as with Paradise, and just as with the final heaven and hell.
As you mention a little further, we "are not in our full state of humanity unless our soul and body are united." The torment of the departed is in the unnatural state of existence of the soul without the body, the restoration of which union will result in a renewed life. Until such time (Final Judgemnt), the soul will be alive in a state that is not full life as evidenced from the belief that they cannot repent. Just the fact that repentance is no longer an option wold be a torment to all the saints.