Here is the story of Jack from the 2007 website.
http://websites.horrornights.be/2007site/orlando/taleofjack.html
It also says that Jack was searching the world for haunts for his carnival which is how he came upon Freddy, Jason, and Leatherface.
Thanks for posting that. Cool to see. The USH backstory was definitely MUCH more detailed, with "vintage" video footage of him growing up, etc. It was apart of the "Terror Tram" overlay to the Backlot Tram Tour. The whole drive down the hill to the sets featured a video pre-show of sorts that sets up the entire event. I wish there was an opportunity for something like that in Orlando. Everything about the event felt so much more connected and clear.
I think it's cool that they put effort into the website, but I ABSOLUTELY am not a believe of *having to read it* to understand what's going on. A good story should be clear on it's own - be it through the use of a pre-show like USH or some other means - but you should not *only* "Get it" if you read things on a website before hand.
Last year's event was so detached to me that my friend actually had to explain themes and backstories to me as we walk through. He's a writer so he studied up on the stuff, otherwise I would have had no clue why things were themed the way that they were.
There's story, and then there's spectacle. Both are important, and some times too much of either can harm the overall product. Though Universal is obsessed with host "icon" characters these days, they rely much more on spectacle, which really make it even harder to sometimes understand the STORY of why all the mazes fit together and mesh as one experience.
Would anyone have understood why Freddy / Jason / Leatherface were involved without knowing the background that you mentioned or learning about it at USH? No. They'd think "Oh neat, these are popular movies and they're scary so they're at the Halloween event" - not "Jack brought them here as his side show." I wish they'd get back to balancing story with spectacle like they used to ten or so years ago. It's for that reason that I feel like the event has just been lacking for the last several years.