Giordano - those myth similarities have been denounced pretty heavily. There is no historical books/claims that support all those virgin mothers, Dec 25th birthdays, rose from the dead, etc...
Just the fact that they put Jesus' birth on December 25th or winter solstice, shows a lack of research, and should be a red flag as to how trustworthy the claims are. And most of the myths of those other ones don't list a birth date.
There are a few threads about it here, or you could look up the myths about these god-men for themselves and see what they have to say.