I've addressed these concerns. It does not raise questions for me because long before the existence of any of the gods mentioned, messianic prophecies were spoken of on the earth, including as early as 3700 BC by Enoch. It not beyond the realm of possibility (probably likely) that societies filled in the blanks on their own by assigining an Osiris, a Mithra, a part of their society to be the one to fulfill that prophecy.
The dates, to me, are of little importance. Our entire calendar is based on the sun, so why is it of any significance that the dates we celebrate the birth, death, and resurrection of Jesus are dates that have held cultural significance even before the birth of Jesus? Of course the dates will be aligned. They can be posted repeatedly, a million times, and these numbers and dates will provide nothing conclusive concerning the existence or non-existence of Jesus Christ.
Now, I know that isn't good enough physical proof for you, but it's certainly enough to cast reasonable doubt into what you and MiamiHeat are trying to establish as irrefutable evidence (which it is not, and no court of law would say that it is).
I've said this before and I'll say it again now. I know that there are unknowns in the Bible, and in the Christian faith. I struggle with them from time to time, and I search for answers to those questions. But, eliminating God from the equation just introduces a whole new set of unknowns and questions. By saying you KNOW there is no god, you are claiming that you know that everything came from nothing...that life came from non-life...that order came from chaos...that natural law came from randomness. All the while, faced with ZERO physical evidence that any of that happened. NONE. But you can say beyond a shadow of a doubt that all that happened naturally...because a supreme being does not exist. Sounds to me like a giant leap of faith.