Hello!
Before taking a look at the site for the live implementation I'd like to examine this code of yours, if that would be possible, so I can properly assess what would go into getting this as you want it.
I am assuming those file formats are not actual variations of the product(cannot be purchased independently), but are just multiple downloads added for the downloadable product. Am I correct?
Also wp and wc versions in use are an important metric so please forward this info too.
Regards,
Dobri