Why can't you just pay them directly and have them give you a W-8-BEN-E?
It's just a business expense. Most countries have a treaty with the USA that prevents double taxation. The W8-BEN-E just tells the US gov't (if they ask for it on an audit) that you do not have to file a 1099 for them.

Act as a pass-through LLC for the funders, make yourself a free commission.