I've always annoyed people trying to apply these tests, because I stop with, "I don't know anything more about that person. All you've given me is a name. That doesn't contain the information you're asking for." Or a picture. Or whatever. Because it could be boy named Sue or a white Irish kid named Javier.
Sometimes when I'm naming characters they just tell me. Sometimes I go looking for things that match. I like using ethnic names because it's a chance for wider representation. I often look up the demographics of a region to find locally common names and ethnic groups. But every once in a while they do something off-pattern, like sex-swapped names, or the Louisiana woman who started screaming curses in Italian.
Assumptions are bug spots that'll stop you from seeing what's really in front of you.