I only looked at the first link,

http://www.sanfords.net/Framed_pages/origins_of_christianity.shtml

Just skimming it I can tell that it is mostly bullshit. Just minimal research into the backgrounds of these other characters will show you that many of the "facts" about each of them are entirely made up. Horus was never born of a virgin, in fact, his origin myth is pretty explicit with his father being torn apart and his mother reconstructing him, but discovering the genitals to be missing, forcing her to build a new one for him which she puts into use right away resulting in the birth of Horus.

Stuff like the claim he was born in a cave/manger on December 25 (what's with the "/"? Those things are so far apart it is about like saying someone was hit by a bicycle/schoolbus) was completely pulled out of someone's anal cavity. As was "Anup the Baptizer", which actually gave me a good chuckle. Go ahead, google search "Anup the Baptizer". You'll find plenty of hits, but every instance you will find of him is sourced from the same place georgec link is using for a source (a 19th century poet, it would seem), some of them debunking the made up claim, others blindly perpetuating it.

Dig deep enough and you'll find there is no "Anup the Baptizer" in Egyptian mythology.

While there are some striking similarities between the teachings of Jesus and Buddha, you'll find many of the claims of their connection in that link are also completely bunk.

All three bullets on Prometheus were accurate enough, but if you are familiar with the story of Prometheus and the story of Jesus, then it is a pretty obvious stretch to make the claim that the Jesus narrative is in anyway a copy of the story of Prometheus.

When you take out all the made up stuff, you're left with little more than a number of minor coincidences. Many of them only coincidences if your word them right (like with Prometheus).