How is it that you would consider prophecies written by previous writers, and then fulfilled by future writers to be evidence of anything? I'll give you a quick little example as to explain why this doesn't show ANYTHING.
NT Writer: Hmm... so let's see here... I'll have Jesus been a male! OH, and a couple passages in the OT suggest that the Messiah will ride on a donkey, so I'd better put that in.
What would stop the authors of the NT from altering Jesus' life, if he existed, to fit the prophecies. It's not as if the OT and the NT were written in conjunction, after all.
NT Writer: Hmm... so let's see here... I'll have Jesus been a male! OH, and a couple passages in the OT suggest that the Messiah will ride on a donkey, so I'd better put that in.
What would stop the authors of the NT from altering Jesus' life, if he existed, to fit the prophecies. It's not as if the OT and the NT were written in conjunction, after all.