I’ve also got you covered there:
Tongue drum: Der Froschkönig - Lowrider 3 in Oldenburg, Germany - #326 by Tokoloshe. The plans for the main plate it will be uploaded soonish, after its completely done. 
Cajon: Cajon with legs.
Can’t help you with the moon, but a rocket shelf: Rocket Shelf.
I think we need to start a collection of all the plans for kids. 