Hello,
For creating phase :
I see a solution to create all product and variants at the same time, the CSV file,
here
a documentation that will details you how to import and beside generate product with variants.
For the front end variants selection don't forget that you have different display options, in the Main HikaShop Configuration, Display tab and Product Options tab.
You will see this :
In this dropdown, you will have
several display options to better fit all your variants possibilities, don't forget in each Characteristics config to
Characteristics selection method to
Inherit, that will able your main config to be applied.
Hope this will fit your needs.
Regards