It's interesting that Christians mention secular theologians as if they have an agenda contrary to yours. Do you seriously believe that every secular theologian is an anti-Christian theologian? If so, that is quite some persecution complex you've got there. There are many, many Christian scholars that strive to reach historical truth about the bible, and all credit to them. Much of it has been sheer brilliance and a magnificent contribution to the field of study. Similarly there are many many secular theologians that strive for the same. What makes you think that secular theologians are incapable of rational inquiry? Is your position that precarious in your view?
However, there exist a number of charlatans that colour their 'research' (and I use the term loosely!) with their pre-existing assumptions on what the outcome will be. This goes for Christians and anti-Christian scholars alike, and both should be derided on the same grounds - intellectual dishonesty.
Let's talk New Testament historicity with regard to the resurrection. Bear in mind that this is one of the most crucial, if not THE most crucial occasion in Christian theology and of course in the lives of the gospel writers - this is some of the stuff that is the foundation of western theology for hundreds of years to come. Matthew, Mark, Luke and John really ought to have been singing from the same hymn sheet with regard to what happened because they were supposedly there for much of it.
So, bearing this in mind, if we are to believe that the gospels were written by Matthew, Mark, Luke and John themsleves, there really ought to be some continuity in their accounts. They were there, right? It is the most momentous event in their lives. They wouldn't forget what happened.... would they?
Let's have a look...
What time did the women visit the tomb?
Matthew: "as it began to dawn" (28:1)
Mark: "very early in the morning . . . at the rising of the sun" (16:2, KJV); "when the sun had risen" (NRSV); "just after sunrise" (NIV)
Luke: "very early in the morning" (24:1, KJV) "at early dawn" (NRSV)
John: "when it was yet dark" (20:1)
Who were the women?
Matthew: Mary Magdalene and the other Mary (28:1)
Mark: Mary Magdalene, the mother of James, and Salome (16:1)
Luke: Mary Magdalene, Joanna, Mary the mother of James, and other women (24:10)
John: Mary Magdalene (20:1)
What was their purpose?
Matthew: to see the tomb (28:1)
Mark: had already seen the tomb (15:47), brought spices (16:1)
Luke: had already seen the tomb (23:55), brought spices (24:1)
John: the body had already been spiced before they arrived (19:39,40)
Was the tomb open when they arrived?
Matthew: No (28:2)
Mark: Yes (16:4)
Luke: Yes (24:2)
John: Yes (20:1)
Who was at the tomb when they arrived?
Matthew: One angel (28:2-7)
Mark: One young man (16:5)
Luke: Two men (24:4)
John: Two angels (20:12)
Where were these messengers situated?
Matthew: Angel sitting on the stone (28:2)
Mark: Young man sitting inside, on the right (16:5)
Luke: Two men standing inside (24:4)
John: Two angels sitting on each end of the bed (20:12)
What did the messenger(s) say?
Matthew: "Fear not ye: for I know that ye seek Jesus, which was crucified. He is not here for he is risen, as he said. Come, see the place where the Lord lay. And go quickly, and tell his disciples that he is risen from the dead: and, behold, he goeth before you into Galilee; there shall ye see him: lo, I have told you." (28:5-7)
Mark: "Be not afrighted: Ye seek Jesus of Nazareth, which was crucified: he is risen; he is not here: behold the place where they laid him. But go your way, tell his disciples and Peter that he goeth before you into Galilee: there shall ye see him, as he said unto you." (16:6-7)
Luke: "Why seek ye the living among the dead? He is not here, but is risen: remember how he spake unto you when he was yet in Galilee, Saying, The Son of man must be delivered into the hands of sinful men, and be crucified, and the third day rise again." (24:5-7)
John: "Woman, why weepest thou?" (20:13)
Did the women tell what happened?
Matthew: Yes (28:8)
Mark: No. "Neither said they any thing to any man." (16:8)
Luke: Yes. "And they returned from the tomb and told all these things to the eleven, and to all the rest." (24:9, 22-24)
John: Yes (20:18)
When Mary returned from the tomb, did she know Jesus had been resurrected?
Matthew: Yes (28:7-8)
Mark: Yes (16:10,11)
Luke: Yes (24:6-9,23)
John: No (20:2)
When did Mary first see Jesus?
Matthew: Before she returned to the disciples (28:9)
Mark: Before she returned to the disciples (16:9,10)
John: After she returned to the disciples (20:2,14)
Could Jesus be touched after the resurrection?
Matthew: Yes (28:9)
John: No (20:17), Yes (20:27)
After the women, to whom did Jesus first appear?
Matthew: Eleven disciples (28:16)
Mark: Two disciples in the country, later to eleven (16:12,14)
Luke: Two disciples in Emmaus, later to eleven (24:13,36)
John: Ten disciples (Judas and Thomas were absent) (20:19, 24)
Paul: First to Cephas (Peter), then to the twelve. (Twelve? Judas was dead). (I Corinthians 15:5)
Where did Jesus first appear to the disciples?
Matthew: On a mountain in Galilee (60-100 miles away) (28:16-17)
Mark: To two in the country, to eleven "as they sat at meat" (16:12,14)
Luke: In Emmaus (about seven miles away) at evening, to the rest in a room in Jerusalem later that night. (24:31, 36)
John: In a room, at evening (20:19)
Did the disciples believe the two men?
Mark: No (16:13)
Luke: Yes (24:34--it is the group speaking here, not the two)
What happened at the appearance?
Matthew: Disciples worshipped, some doubted, "Go preach." (28:17-20)
Mark: Jesus reprimanded them, said "Go preach" (16:14-19)
Luke: Christ incognito, vanishing act, materialized out of thin air, reprimand, supper (24:13-51)
John: Passed through solid door, disciples happy, Jesus blesses them, no reprimand (21:19-23)
Did Jesus stay on earth for a while?
Mark: No (16:19) Compare 16:14 with John 20:19 to show that this was all done on Sunday
Luke: No (24:50-52) It all happened on Sunday
John: Yes, at least eight days (20:26, 21:1-22)
Acts: Yes, at least forty days (1:3)
Where did the ascension take place?
Matthew: No ascension. Book ends on mountain in Galilee
Mark: In or near Jerusalem, after supper (16:19)
Luke: In Bethany, very close to Jerusalem, after supper (24:50-51)
John: No ascension
Paul: No ascension
Acts: Ascended from Mount of Olives (1:9-12)
Put simply, it is difficult to accept that the gospels were written by the alleged authors themselves when there are so many discrepancies in their accounts. And these are just the resurrection accounts!
New Testament literal historicity? Good luck.....
I'd say the best you can hope for is that the gospels, such as they are, may represent the beliefs and emphases of Matthew, Mark, Luke and John, but were passed own through oral tradition, losing something along the way, and eventually put in writing by others who wrote in that author's name to lend it more authenticity than it might otherwise have been granted. How else would such errata and inconsistencies have crept in, and why were the accounts so different in simple details?
I'd say faith is the better game plan....