Bugs life is good but may be a bit intense. Hopper the grasshopper is an animatronic huge thing that comes out in a cloud of smoke near the stage which is loud and the smoke is a bit daunting, especially if you're closer to the front. My daughter loved it when she was 4, but we just went last week (she'll be 9 next month) and it scared the poop out of her! The stinger is part of the chair, if you lean forward, you won't feel it. You'll know it's coming too. Also, I think at some point, there is a slight spray of "poison" which scared some kids in the audience. I don't remember a snake...but it's possible....if it's too scary, take off the glasses or walk out. It's not worth having a terrified child, but like I said, my daughter loved it when she was little and thought the sting and the poison and hopper were hilarious.
We didn't do the American Idol thing, but Monsters Inc laugh floor is soooooo funny. Then again, we like really cheesy humor. You can text in jokes before the show and if they're picked, they'll be read and tell your (or childs) name and hotel. They randomly choose people in the audience and they show up on a big screen where one of the monster comedians will ask a simple question like "where are you from" and then turn it into a joke. Some things may go over a 4 year olds head, but for the most part, it's great fun and my daughter wanted to do it time and again. We did get lucky that we were there during the halloween party so it wasn't a full audience. I'm not sure if that made it better or not? I would say it's a not miss.