Seems that all of these religions came from a common source. What was the source?
Well, the Hebrew scriptures begin with the books of Moses. And he grew up in Pharaoh's house, studying Egyptian theology.
Then Jesus grew up studying the scriptures from Moses on. He did spend some time in Egypt apparently, but he was only 2.
I suspect he was interested in stuff like this and learned about the Osiris and Horus myths and such on his own.
Horus by the way carried the title "krst" which means "the anointed one." "Christ" also means "the anointed one."