The best way to fully understand the complexity of a product is to model it in real dimensions. That’s why I always enjoy doing things like this, even more with kinder toys.
Besides the normal restrictions for toys like this (small parts, toxicity, and others) most of kinder toys have a beautiful way to solve product situations. Assembly, instructions, draft angle and not least important, the packing into the capsule!
Being caricatures of cars or something like that, the simplicity of each shape is gorgeous. The thickness of the snaps and pins are optimized. The fitting tolerances and the material usage are the bests. No flow issues, no shrink marks, low ejector marks and so on.
The modeling process was using photo references and a caliper.
Having only one, was a bit tricky to get some dimensions due to the small scale. If I had two toys, I would be able to cut some pieces and measure them from inside out.
To get a decent printable model, I scale up by 2.5 factor to avoid fragile parts for FDM printers.
The model in real dimensions and the printable is available at CGTrader buggy Toy
other toy you may like: Squirtle