There's a big difference between realism and deliberate historical revisionism. Not even the "heretical" Dutch had any interaction at all with the Japanese beyond trade, let alone coming [i]en masse[/i] and starting a massive crime family. Including the existence of a European (or, indeed, non-Japanese) family in Japan dating back from before the 50s basically requires erasing a significant portion of Japan's history, and that's extremely problematic. Unless you're willing to incorporate this foreigner-friendly Japan's history into your setting, you're very clearly expressing your unwillingness to use Japan as anything but a condiment to the story you want to tell, which is [i]extremely[/i] racist.

The fact that you're unironically using "oriental" definitely implies that you've got some racist feelings you're showing through here. The word oriental comes straight from old, European, and above all else [i]horribly racist[/i] usage, describing anyone from Eastern Asia, regardless of their culture or race. It's akin to calling a Native American an Indian. If you're going to set something in Asia, at least be courteous enough to refer to the inhabitants correctly and learn their history.