The evidence for or against the existence of John Frum is of no real value in the quest for an historical Jesus.
It is completely logically fallacious to argue that Jesus did or did not exist because John Frum was or was not a figure of history.
The Quest for an historical Jesus REQUIRES EVIDENCE from antiquity.
We have HUNDREDS of manuscripts and Codices with stories of Jesus of Nazareth and they are ALL from the 2nd century or later.
Jesus of Nazareth is described as a Myth character in the HUNDREDS of existing manuscripts and Codices.
Based on these existing manuscripts and Codices the Jesus character was INVENTED in the 2nd century or later.
Apologetic sources claimed the Fall of the Temple of the Jewish God was because the Jews Killed Jesus the Son of their own God.
Those who believed the propaganda were called Christians.
Hippolytus' Against the Jews
7. But why, O prophet, tell us, and for what reason, was the temple made desolate?........ it was because they killed the Son of their Benefactor
Aristides' Apology
The Christians, then, trace the beginning of their religion from Jesus the Messiah; and he is named the Son of God Most High. And it is said that God came down from heaven, and from a Hebrew virgin assumed and clothed himself with flesh......But he himself was pierced by the Jews......And hence also those of the present day who believe that preaching are called Christians, and they have become famous.
Justin Martyr's Apology
Accordingly, these things have happened to you in fairness and justice, for you have slain the Just One, and His prophets before Him; and now you reject those who hope in Him, and in Him who sent Him--God the Almighty and Maker of all things--cursing in your synagogues those that believe on Christ.
Tertullian's Answer to the Jews
....In such wise, therefore, did Daniel predict concerning Him, as to show both when and in what time He was to set the nations free; and how, after the passion of the Christ, that city had to be exterminated....
Lactantius "On How the Persecutors Died
....I find it written, Jesus Christ was crucified by the Jews.
The fabrication of the propaganda that the Jews Killed Jesus the Son of their own God was as a direct result of the Fall of the Jewish Temple of God c 70 CE.
All stories of Jesus of Nazareth was composed AFTER c 70 CE or AFTER the writings attributed to Suetonius or no earlier than the start of the 2nd century.
All existing stories of Jesus of Nazareth are dated to the 2nd century or later.
All mention of people called Christians who believed the Jesus story are from the 2nd century or later.
The Jesus character was a product of fiction and supposed prophecies in Hebrew Scripture like the book Daniel.