You left out Pope Julius the first. Who set up Dec 25th as Christmas because it was his own birthday.
Also Horus' birthday was on the 5th day of the Epagomenal Days, which takes place in late August or sometimes in late July
No mention of Papa Nurgle or the God Emperor of Mankind.
but...Hercules birthday was in march 0_0
29th of march 0_0 well...their chronology was way outside outs....but that's the rough date 0_0