For kids I'd go the fruit tort.
You can pre-bake the shell if you want. And pre-make the custard.
In fact, now that I think of it you could bake mini shells so each child or pair could assemble their own....

Lamingtons are great for kids to make - just a simple dark chocolate (less sugar) ganache and coconut and they can roll it around in the bowls themselves.

ETA -
I didn't see your post.
For mini-cupcakes/cones I'd probably go with a lamington style icing - they can dip into the ganache/chocolate then dip into coconut.