From various reviews and discussion boards:
*Only side to side movement, everything else comes from the visual experience.
*No, there's side to side and up and down, with drops of up to 10 feet that correspond to on-screen "swooping."
*No, it's 10 inches.
*You are never more than four feet off the ground.
*No, the floor platform moves out from under you and you are suspended.
ANYWAY, the only thing I can guess is that the room is somewhat dark and people are thinking about things other than 'gosh, let me analyze this for my blog' when they're on the ride.
In a charming and adorable highlight, just about everyone has something nice to say about the fact that you can feel your banshee "breathing." This is actually what convinced me that maybe I'd be okay, because I had trouble watching 'Up' when they're clambering around on the dirigible, but no problem whatsoever watching the swoopy flight in 'How to Train Your Dragon 2,' because I was confident Toothless would catch him.