Well for children I'd just use the brazilian hack I told you about, where I install all the games they like to play, and they will all be in the system home menu. No need to launch any hack to see them. That's what I did for my niece and nephew, both of them only want to play some games that I installed, they aren't interested in homebrew, or cheats. But if you're interested in other stuff take a look at
the definitive guide to wii u hacking There is a section about game hacks that are easy to use.