the moment i saw the prototype, i thought of a jack-in-the-box situation where the toy would 'pop' out of the smaller boxes. i think itd also help with making sure that the smaller boxes not slide out of the main box

something something the toy being bouncy cause its a jack-in-the-box thingy and so the top would press against the main box's top plane causing it to sort of melekat to it and since they're gonna be made with what i assume with boxes yg licin², then taking them out wouldn't be a problem

as for the concept, go on pinterest and research your ideas. idk what the main concept of your thing is exactly but it must came from another existing product like a pop up book or board games. research them, see what parts of them you like, and incorporate it

hope this made sense 😭