I think
Kyriakos would be ok if you were in Greece, but as a stand alone first name in Australia for example, I would say no. It is too complicated and doesn't particularly flow well in my opinion.
Having said that, I do really like ethic names and I don't think you should limit yourself to your own ethnicity in naming a child, but I do think you have to be reasonable.
Kyriakos and Kiyriyakan, area mouthful (in any language), and aren't really attractive names full stop.