Hi there,
This is Bogdan from Romania.
I'm a mechanical engineer - specialized in the industrial robotic field, 3D designer and modeler (from time to time and some projects I could make the functional prototype too).
I'm doing product design, industrial design, reverse engineering, ideation, etc.
I have over 15 years experience working on various systems/devices across multiple industries, from concept to launch.
.1 - as it is a multi-component/part toy/set, would be compulsory to have a 3d model of each part individually and a few assemblies to see how the parts fits together... (how would be the lego brick not to fit with some new modules?...)
3 - after identifying all the parts/modules and have a clear classification, you need to prepare the guiding for children on how to make different end assemblies
4 - depending on the number of modules, will have to make a rapid prototyping - 3d printing, thus will need to have prototyping ready models (which are different than the manufacturing models)
5 - with the prototypes in your hands, and after an extensive "play and try" process, will decide if you want/need any modifications/adjustments/changes...
6 - if happy with them you may go to the next step - series zero.../manufacturing
Regards
Bogdan