Thanks! That does sound better. (I was obviously using Google Translate on Pixiv, and know enough to tell when something sounds off, but not enough to second-guess it correctly ^_^;)

I do think Tibet-chan | チベットちゃん is a common enough fanon name to use in the absence of a canon one. (Similar to Poor-chan and...is it Bear-ko?) The others are just a case of "eh, we have to call them something, so...."

With the African girl, "Savannah-chan" may not be common, but that's the only "name" I've ever seen her given (as opposed to descriptions, like "indigenous African girl" or "girl from the savannah"). So at least it's not elevating one fanon name and ignoring a bunch of others. IDK how the fest mods feel about sticking with English here, but I'd definitely be happy just making the tag "Savannah-chan" without trying to back-translate it at all. (Back-translation could be added later if she ever caught on in the Japanese fandom.)

The Middle Eastern girl is the one I'm not at all sure about. Especially since I don't think what we see of her is distinctive enough to identify even the country she's from :/