These IRS forms are always confusing!

There's a freelance web developer in Tunisia who I hire sometimes. I also sometimes hire an assistant who lives in Hungary. They are not US citizens nor legal aliens. My questions are:

1. Do I still need to get them to fill out and sign form W-8BEN?

2. Judging by the information they ask in form W-8BEN, it looks like there's a treaty between both these countries and the US for tax collection purposes. Does this mean that once they fill out the form, I have to withhold 30% from their payment? Or do they (the freelancers) have to start filing/paying income taxes to the US?

3. The form asks for the Beneficial Owner's Social Security number, an ITIN, and a Foreign Tax ID number. What if a freelancer I hire happens to have a SS number but does NOT live in the US and all work performed was done OUTSIDE of the US?. 

Sorry for all the questions. I'm sure others have similar situations.

Thanks!