For Australia / New Zealand we allow both answers for multiple reasons of debate including which is more southerly and whether or not English is a dejure language.
Not as of this featured quiz. As per the quote from the Constitution: "The state language of Tajikistan shall be Tajik. Russian shall be the language of international communication." The state language of Tajikistan, which I understand to be synonymous with official national language, is Tajik, and only Tajik.
https://en.wikipedia.org/wiki/List_of_countries_by_southernmost_point
Also what does Fiji have to do with French? 🤔