Theseus descended before Heracles and was brought up by him (leaving behind Theseus's blood brother, Piritheus). We know that both Orpheus and Heracles made their descents after the Argo, but not the relative timing -- though I have seen a version that claimed that Orpheus got in so easily because Cerberus was still shook up from his captivity above ground.

Either way, all three returns from Hades were a generation before Troy: Nestor is the last man alive from that generation, and he was a young man at the war of the Lapiths and Centaurs, which started at Piritheus's wedding.

---L.