HiSir,
I have read all your requirements, i can fulfill your requiremnts since i have worked all types of products upload like creating catagories, configurable product, simple product, product variations, dropdowns etc. We have a team of 17 members, so that according to your requirement i will arrange my people on this project. Till now we have done product upload into 70+ sites like Magneto, ecommerce, woocommerce, joomla, Shopify, x-cart, prestashop etc. I will provide you the sites and sample work which we have done earlier and i will show you a sample product uploaded into your sites as well to make sure i am the best to fulfill your requirement.