I've used KDE on my convertible during uni and it worked pretty good. I mean for a GUI oriented setup your options are pretty much KDE, gnome, cinnamon, xfce (don't know how good that is with touch though) or cosmic (is that out yet? Idk tbh).
Afaik gnome and kde both have good touchscreen support, maybe you'll need to do some slight modifications, so I'd say just try them out and see what you like.
A friend of mine got his son to use Linux by just not providing an alternative, he installed Debian edu (don't know if that's the name, but basically a Debian spin for kids with parental restrictions and stuff) on an old laptop for him and that's what he used. Once he got his own PC it was over though since he wanted to play Fortnite so bad that he bought windows for that. He still dual boots Fedora, but I don't think he has used it since the windows partition is there.
I think the thing is you can't really get kids (or people in general for that matter) into Linux the way you are probably into it and interested in it. At least not if they're not already interested in it on their own. They will learn how to use it sure, but not the way we're used to using Linux, understanding the intricacies of the system, keeping the system safe,... They'll probably find a way to do what they already do on windows and ignore that the OS is different.