While there are a lot of other threads regarding -ese demonyms, I doubt this query has not been cast. If there is a series of denonyms in a question like the following, would you still use 'a Japanese person'?
Are you an Italian, an American, a Peruvian, a Russian, a Japanese, a Korean, or an Australian?
Hiro
Are you an Italian, an American, a Peruvian, a Russian, a Japanese, a Korean, or an Australian?
Hiro