Adding Additional Product Fields (UPC, Size)

Have a store running 2.0.15. We want to start entering weight, size, and UPC information for the products. My data entry person claims these fields are not available. Is weight not available if the shipping settings are not set to calculate by weight and if so, is there a way around that so weight can be entered just for internal informational purposes?

Same for size and UPC. We want to enter size but not as an option, just for internal info purposes along with UPC. Want to keep our existing SKU values but would also like to list UPC for info purposes.

Size (of External product box) and Weight should both be available via Edit Product > Shipping Properties. You could, however, create Features for these, as is shown in the default CS-Cart install/demo. Products > Product Features. See the KB Product Features Article.