Interestingly, in both lands the guest becomes the fictional character.
In Diagon Alley, you can acquire gear and training to become a wizard.
In flight of passage, you get transferred into a half-na'vi body.
...now that I think of it, how does that work exactly? If in flight of passage we jump right into an avatar body as it begins to go through a banshee-riding coming-of-age ritual, who was the poor schlub who had to do the hard work of climbing the mountain in those bodies and wrangling onto a wild banshee, just to hop out when the fun part starts?
And how are there enough Avatar bodies up there to ensure a compatible DNA match with all the guests Alpha Centauri Expeditions wants to accommodate? Do they keep a big pile of them sleeping up on the mountain, stacked up like cordwood? Do they have to pay some Na'vi to shoo away all the banshees that try to eat them? Is there a big conveyor belt set up to return all the Avatar bodies to the top of the mountain once the guests are done with them, like at a tube slide at a water park?