Wow that sounds interesting! The more stuff the kids can do the better. Of note though most of kids that want to run trains at most of my events are 2-5 years old. However of interest during the Polar Express events we get a lot of the older children and teens young adults visiting the event. I have found over several years that teen girls I guess age 12 or so and up, tend to stick around for a long time at the Christmas /Polar Express layout waiting to try out all the trains and animation/ sound buttons, and looking at finding all the many scenic details animations and scenes. So for most shows the simple LionChief controls a few sound and animation buttons keep there interest for a long time (parents wear out and want the kids to move on).
I have found at the train shows that letting older teens in to run the switching layout they are happy to do something more complex for a half hour or so.