Heh, I was about to tl;dr but I read through your post and I really like it. The trivia game is just awesome
I could help with things as temporary block protection to avoid cheating. However, I don't really want to use /item too much. You should focus on getting sponsors for the games instead!
I don't really get the Scavenger hunt idea, since players would just be able to run away, hide behind a tree and craft a lever, right? I mean, since they can go all over the map they can just prepare a chest full of levers before the game starts. Work on that please!
Great work so far.