What doesn't fit about it? Doesn't Juliette wear glasses? Considering there's lamia creatures, are catgirls that much of a stretch?
Lamia count as monsters while, call me crazy, it doesn't seem like the catgirl in this picture does. In the general fantasy that includes slimes, fairies, goblins,
tentacle monsters, succubi, and variants thereof to be monsters, catgirls are somtimes-on, sometimes-off. Of course, the futa elves and non-futa elves seem to also count as both mobs and NPCs, and orcs are hanging around, so there's that, but, again, boobsgames has
quite a bit of artwork that, yes, features the same style, but would otherwise not mesh with the game.
Felt like saying so last time, but didn't think it necessary; to entertain the thought,
maybe they would be characters in the city that's gated off (the background seems to be at least a two-story building, of which there are only two in-game currently, neither of which fit the image), if it were ever accessible, but even then I doubt boobsgames would reveal them
so far in advance of the content they would/could feature in that speculation on them being in the game (what you're doing) would take place months to years in advance.
Besides which, the majority of the game currently seems to take place in a semi-countryside setting while this looks by comparison fancy as fuck, besides which, detailed backgrounds of the environment are not yet a "thing," tending to instead just keep the sprite area as the background.