Does the 1st Corinthians 15 creed relay witness testimony?

Introduction

Historians widely agree that Paul wrote the letter of 1 Corinthians around AD 53-54. In chapter 15, he says “For I delivered to you as of first importance what I also received, that…,” and he proceeds to share what scholars widely agree to be pre-Pauline creedal quote/confession. The creed goes at least from v3-5, with 6-7 likely also being creedal. (Note: Though 6-7 may or may not be a different creed.)

Rather than being some Christian fabrication, is this report of Jesus appearing to various witnesses ultimately a relaying of testimony from purported witnesses themselves? Is this content an echo of alleged persons who claimed to have seen Jesus? Was it built faithfully from eyewitness testimony?

Historians largely agree: it was witness testimony

• Pinchas Lapide: "[T]his unified piece of tradition which soon was solidified into a formula of faith may be considered as a statement of eyewitnesses for whom the experience of the resurrection became the turning point of their lives.” [The Resurrection of Jesus, 99.]
• Kirk R MacGregor: “Taken together, these considerations have led a broad spectrum of scholars from widely divergent schools of thought to identify this creed as eyewitness testimony of those who believed they saw literal appearances of Jesus alive after his death.” [“1 Corinthians 15:3b-6a, 7 and the Bodily Resurrection of Jesus” in Journal of the Evangelical Theological Society. Evangelical Theological Society 49(2)(2006): 227.]
• A. M. Hunter: “The passage therefore preserves uniquely early and verifiable testimony. It meets every reasonable demand of historical reliability.” [Works and Words of Jesus (1973) p. 100]
• Hans von Campenhausen: “[T]his account meets all the demands of historical reliability that could possibly be made of such a text,” [“The Events of Easter and the Empty Tomb,” in Tradition and Life in the Early Church (Fortress, 1968), 44.]
• Richard Bauckham: “There can be no doubt that in his own recital of the kerygamatic summary in 1 Corinthians 15 Paul is citing the eyewitness testimony of those who were recipients of resurrection appearances, including the most prominent in the Jerusalem church: Peter (Cephas), the Twelve, and James the brother of Jesus.” [Jesus and the Eyewitnesses (Eerdmans, 2006), 308.]

“Yes, after all…

1st church formed/circulated 1 Cor 15 creed

The 1st church, formed by the apostles in Jerusalem, were in c. AD 30 circulating the 1 Corinthians 15 creed. This full article debates these 7 evidences:
• It originated in c. AD 30-35.
• It catered to Jewish-Christians.
• Its creators are close/identical to 1st church leaders.
• Its creators often discussed “the twelve apostles”.
• Paul’s creedal traditions were from Jerusalem.
• Jerusalem was at least circulating the creed’s facts.
• Its Greek has semitic features.
This is relevant because the teachings of the 1st church reflected that of witnesses.

But no,...
• It displays Hellenistic-source tendencies
• Paul invented it • The 1st church didn’t canonize creeds/traditions

In AD 30 Jerusalem, true Jesus-bio dominated

In c. AD 30 Jerusalem, the ratio of true to false Jesus-biography circulating was overwhelming. The truth was pervasive and dominated. This full article debates these 6 evidences:
• In AD 30-70 Mediterranean, Jesus-bio truths won-out.
• Acts 2 “You all know!” dates to AD 30.
• Jesus-bio witnesses+testimonies flourished in 1st church.
• In general, ECs were honest about Jesus-bio.
• In AD 30 Jerusalem, witnesses killed most false rumors. This is relevant because the creed was circulating in c. AD 30 in/around Jerusalem.

In general, their Jesus-bio relayed witness testimony

The Jesus-biography circulated by early Christians tended to be inherited from eyewitnesses, either directly or indirectly. This full article debates these 6 evidences:
• Most Jesus-bio relayed true witness-derived testimony.
• Usually, early Christian Jesus-bio wasn’t fabricated.
• Early Christians worked to adopt witness-attested Jesus-bio.
• In AD 30-70, witnesses killed off false rumors.
• Early Christians cited named witnesses.
• Papias takes it for granted.
This is relevant because if the Jesus-biography of Christians tended to have originated form purported eyewitnesses themselves, then insofar as the 1 Cor 15 creeds claims are historical in nature, we can expect (all other things being equal) that it too was sourced by the relevant purported eyewitnesses.

In general, early Christians rarely invented Jesus-bio

Early Christians were circulating a lot of claims about Jesus and his ministry, death, and purported resurrection actions on Earth. As a matter of proportion, very few of these in AD 30-70 were fabrications or serious embellishments. This full article debates these 4 evidences:
• In general, early Christians were honest.
• Early Christians would report Jesus-bio honestly.
• They wouldn’t invent the Jesus-bio as we see it.
• They relayed witness testimony.
This is relevant because if it was not invented, it’s most plausibly understood as originating from the relevant eyewitnesses itself. (Every other candidate source would inevitably be spinning a lie.)

But no,... • Counterexamples abound.
• The gospel traditions are full of lies/invention.

“No, after all…

Paul invented 1 Cor 15

The whole 1 Corinthians 15:5-7 content which Paul was allegedly passing down in fact was a complete fabrication by Paul himself. He made all the witneses and these appearances up. This full article debates these 6 evidences:
• It's full of extra-Pauline verbiage.
• Paul’s assumes his audience knew it.
• It too stupidly invites falsification.
• No plausible motive.
• Paul relayed it (1 Cor 15 is pre-Pauline).
• The appearances are multiply attested.
This is relevant because if Paul invented it, then it obviously is not a relaying of eyewitness testimony.