How many Jedi Prophecies are there!? I'm still convinced Kyle's the Chosen One, not Anakin.
As for the fight itself, it can go either way. Most likely, Sids would do what he did to Mace, and play weak to test their power. Obi-Wan would be hard pressed, as Palps isn't as blind as Anakin. Kyle's mixing of force powers may help, if he can do like Yoda and get a force while Sids is attacking Obi-Wan, then they could move in for the kill, unless palps gets up.
He got it from the SW databank. And technically, balance would be achived there, but in a different perspective. If kyle was light, then the power would be released to the light, but if he were dark, then he'd have all the power for himself. It's balance either way, tilted in the favor of either light or dark.
What I can vaguely remember is that it says 'Bring balance to the force' but then thats just general knowledge. However, I am sure someone such as Yoda or Windu tell that it refers to the Sith.
I have no idea who wrote the prophecy yet I doubt Bane would. He is described as brutish and I doubt he would make a prophecy about his own Orders downfall with his personality.