I argued here and here that Gaius Titius Justus was given the name/title "Stephanas" because he dedicated his house and household to the service of the church, and that Paul called him "Stephanas" when referring to him in connection with this benefaction (when writing to the Corinthians, who would have understood the significance of the name). Paul says that the household of Stephanas was the "firstfruits of Achaia" (1 Cor 16:15), and I argued that this signifies that Stephanas was the founding benefactor of the Corinthian church.
Now, Paul also describes Epaenetus as the "firstfruit of Asia for Christ" (Rom 16:5). Now, the name "Epaenetus", means "praised/commended", and, like "Stephanas", also belongs to the semantic field of benefaction. There are numerous inscriptions in which beneficiaries agree to "praise" a benefactor, and Rom 13:3 also appears to use the term in connection with benefactions (so Winter).
The connection between the names "Stephanas" and "Epaenetus" and benefaction is illustrated by an inscription from c24 C.E., in which a synagogue community honors a benefactor:
τοῖς ἄρχουσι καὶ τῷ πολιτεύματι τῶν ἐν Βερενίκῃ Ἰουδαίων ἐπαινέσαι τε αὐτὸν καὶ στεφανοῦν ὀνομαστὶ καθ᾽ ἑκάστην σύνοδον καὶ νουμηνίαν στεφάνωι ἐλαίνωι καὶ λημνίσκωι
the leaders and the politeuma of Judeans in Berenike decided to praise him, to crown him by name at each gathering and new moon with a crown of olive branches and ribbon, ...
Reynolds, Excavations at Sidi Khrebish Benghaxi (Berenice), vol. 1, 1977 p244, no. 17. Translation by Phil Harland (Associations, Synagogues, and Congregations).
All this raises the possibility that Epaenetus was the founding benefactor of the church in Asia and that Paul alludes to his benefaction in Rom 16:5 by calling him the "firstfruits", and by referring to him as "Epaenetus", the name/title that he had received for his benefaction. Perhaps he was Tyrannus (Acts 19:9).
It is surely no coincidence that both of Paul's "firstfruits", Stephanas and Epaenetus, have names that are suggestive of honors commonly given to benefactors, and that their names appear only in connection with their benefactions. This illustrates the practice of giving new names to benefactors in the early church (compare e.g. Joseph-Barnabas and Crispus-Sosthenes).