Fiverr does give permission to certain sellers to use Skype. I don’t know about Facetime. The seller needs permission IF they are going to use Skype to communicate directly with you as a buyer. Now, that isn’t the case if you are hiring them to use Skype to interview someone else for you since that process would not involve you getting their contact information. It would take some work to find a seller you could count on if they are going to do interviews with other people on your behalf, so for that I would suggest someone with a lot of experience and you would be paying well over a $5 base gig fee.
If you are talking about you talking with a seller by Skype, they would need CS permission for that. In that case, the best thing to do is to search for gigs that actually have the word Skype in the gig description. Second, when choosing a seller that offers Skype related services, use a seller that is a leveled seller. I am not saying that to give preference to leveled sellers due to quality because there are some great new sellers.
In this case, the reason that I suggest a leveled seller is because a new seller might not realize they need permission for Skype and if they are in mid-gig with you when Fiverr notices it, the seller might be shut down. If you go with a leveled seller with reviews existing on the gig, chances are better that they do have appropriate permissions.
Finally, you can even ask the seller directly if they’ve obtained Customer Support permission before you place the order. You are still protected to a degree even if something does go wrong, since as a buyer you’ll get a Fiverr credit back if things don’t work out. You’ll have that credit available to use with another seller, but you won’t get a refund all the way back to your credit card or PayPal. I hope that helps!