Hey now, Astronomical Units is SI. Probably. And besides, the way to maximize horniness in text-based games is comparisons, nothing but. If I only ever used units of length and weight, it wouldn't have nearly as much impact. How much is 6 trillion kiloliters anyways? It's difficult for them to visualize, which makes it difficult for the game to have any meaning. It's not much of a game if you remove the plot, after all.
I could use metric units for the stuff that are actual units, sure. I considered making that a setting for a good while, until I thought about the actual work that it would take to implement, and the fact that the log(size) upgrades would make less sense than they currently do.
As for her name, Yuri's a cute name. It sounds vaguely japanese (a culture with quite a few foxes in it), and it's pretty common as a name there since it just means "lily". Her last name, Belyaev, stems from the Belyaev foxes, an experiement held in Russia by Dimitry Belyayev, who I've just realized I've been misspelling his name :|, specifically regarding the creation of truly domesticated foxes in the same ways that wolves and cats were. The foxes made from that experiment were much more amicable to humans, it was valuable research into domestication and biology, and it's even been found that the floppy-ear gene is pretty closely connected to the liking-humans gene, as Belyayev fox kits had slightly floppy ears. Wait no the wikipedia article spells it both ways. I'm in shambles.
I was not previously aware of the Russian handling of last names. It's pretty neat. But, because I'm an author and contain the infinite power of rationalization at my fingertips, I will simply say that Yuri's family previously immigrated to Japan from Russia, then from Japan to America. Or perhaps she's the daughter of a russian and japanese immigrant. Either way, anything can work in America's setting of taking bits and pieces of any/every culture and ignoring how they should really be handled.