Your sites are long and have many things that would have to be refuted. To do that I would have to sit here and quote them point per point and then discuss how archaeological evidence and historical documents dismiss many if not most of these sites.
I am much more comfortable dismissing them by citing the fact they are biased sites and asking the readers here to compare them with more scholarly studies that they would have to leave the web and go to a university library to retrieve (of course typing Mithra into a search engine could lead them to some unbiased works on the web). That said I will not waste hours refuting material that is at best wishful thinking on the part of religious people who can't live with the fact that a Roman Emperor had the power to decide that baby Jesus was born on Dec. 25th (the birth day of that Emperor's ex-god) and that a Roman Emperor had the power to decide that Christian's should worship God on Sunday (the day of worship for said ex-god). That is the gist of the problem here and sensible people can go look it up for themselves without me having to baby them through the process.
I will not waste hours refuting material that is at best wishful thinking on the part of religious people who can't live with the fact ...
So it's those "religious people" who are the biased and dismissive ones unable to face facts here, huh?