I'm waking this thread up, because I got an interesting idea for what to put in the Fear Factor plot.
Now, I'm still all in on enclosing it as a "West End Theater" and putting a quality stage musical in there.
BUT... what if Universal put in an unexpected ride. Based on a book by a famous British author with a unique artistic style, family-friendly nature, and associated nostalgia...
Matilda.
Build a simple dark-ride (trackless or bus bar), that mimics Cat in the Hat's style of going through the storybook. You have a great antagonist in Trunchbull and compelling scenes involving torture and telekinesis. Plus, you can add a cute little "Bruce Bogtrotter's Baked Cakes" shop that sells cupcakes.