Hi there!
I am an international applicant too, and had an skype interview a few days ago.
I was told the questions were going to be about my research proposal and all similar questions posted here already, but no. Nothing like that. I was asked about theoretical issues in comparative biology (like species concepts), and what ifs related to me broadening my research (tell me an alternate research proposal, and another one, and a change of geographical setting, etc). It was very stressing for me since I really wasn't expecting those questions -I'd practiced all the possible questions about my research proposal, the pros and cons, everything!- and there was so much static in the call, that I couldn't understand them properly. Ugh, awful. Not even the classics, why do you want to come here? why are you a good fit? It felt as being in an oral exam.