First congrats for an educational initiative, and second congrats for an educational initiative that can make future people interested in astro-sciences.
I share the same feeling about KSP. Yes, it is much more user-friendly and simplifies a lot of things that kids can't understand. Also, the graphics are appealing, and that's very important for kids, that don't have reached the level of abstraction of adults (it usually takes place during teen years). So 3D terrain you can land on for Orbiter would be highly valuable. But this is done at the sacrifice of the real space-time scales, which I find a bit embarassing in an educative perspective. It doesn't take 3 hours to get to the Moon with a "classic" chemical rocket, and the gas giants (only Jool for now) are in reality very, very far away. Still you realize that, even in the scaled-down universe of KSP, your chances of randomly colliding another orbiting object are extremely low (unless you try to approach it).
Orbiter lacks the "fun features" and the appealing terrain, but no collision detection isn't a problem, a kid will be rather happy to go through the ISS because he missed his docking. They easily understand that there would be a nasty collision IRL. Also, you really feel that the distances to other planets are huge and that an interplanetary trip is a great challenge. About TransX/IMFD, they are obviously much too abstract and complex for kids, and also for probably most of the adults (including myself, I can use them but I really have a hard time doing so).
Now, I know this isn't in the spirit of Orbiter-Forum, but, in the "Orbiter-for-kids-perspective" would a "full-auto" IMFD be possible ? Like you enter "Mars", press a "compute" button, and it gives you a list of launch windows plus a vector target on the HUD (again, visual stuff, a crosshair with "to Mars" written near it). That would be OK for kids I think. With a big timer on the HUD telling when to engage and when kill the engines, that would work. A view of the Solar System with the orbits of planets and your trajectory would be essential, as it shows
what happens (from inside the ship, the transfer can look like pure magic).
Just my :2cents: and congrats again.
Edit : also, for kids, a "purified" OrbitMFD, with less values. There are a lot of complex acronyms there and you don't need to understand all to use it. No problems for adults but kids would appreciable something a bit easier to read.