I agree with most of what you've written here Cassius, but when it comes to what the Vatican knew or didn't know...well, I still can't quite get there.
Consider first that neither the Vatican nor anyone else even knows what Jesus or ANY of his disciples looked like. We have an apocryphal description of St. Paul that emerged in the second century (nearly a hundred years after his death), and it may or may not be accurate–no one will ever know. And...that's it. There's no biblical figure for whom a contemporary image survives.
It would be another hundred years after the apocryphal story of St. Paul until we finally got the first portrait of a Roman Pontiff. The likenesses of the ten predecessors of Pope Anicetus (and those of many of his successors) will forever remain obscure to history.
But look much more recently than that! Almost everyone who reads English Literature with any kind of depth will be familiar with the Shakespeare authorship dispute. While I personally believe that centuries of scholarship has settled that question, there is another debate that's almost as astonishing–no one can say for certain whether the Chandos Portrait, the bard's most well-known likeness, is actually him or someone else. We can't say for certain that any of the surviving and alleged portraits were made in his own lifetime.
We don't know for certain what Chaucer looked like; we don't know what the crowned heads of medieval Europe looked like.
As for my opinion on surviving writings...that will have to wait until after dinner!