Actually, even those claims are just early church traditions. If you carefully read Matthew and John, you'll find that neither writer claims to have known Jesus. Historical-critical New Testament scholars, including Christian ones, are almost completely in consensus that none of the gospels were written by eyewitnesses, and that none of them claim to be.

The lone exceptions among scholars are fundamentalist Christians, who already put the cart before their scholarly horse.

John, by the way, in the view of most scholars, wasn't even born yet when Jesus died.