Hey, thanks for your interest!
Officially yes, there are females in the setting, but it's unlikely any of the named characters will ever be female. None of them are in GT, certainly. So it's probably safe to assume unspecified NPCs are male.
I had to double-check what "Yankee" meant in Japanese, my memory was a little vague. From what I understand, it's a specific sub-culture of juvenile delinquents, right? So the question is, is Scratch more of a youth gang type who just does some computer stuff, or is he an actual nerd? And that's actually a tough question. I'd say he's MOSTLY nerd, like Donatello from Teenage Mutant Ninja Turtles. He "does machines." And he's a bit of a "soft boy" compared to Mezz. But he's been in fights, and survived. He just has a much lower success rate there, which is why he tends to stay back at HQ. But on the other hand, he's not the guy wearing swirly glasses and talking like a robot instead of a person. He's hip, he's cool! He's just...not especially good at fighting, and he IS pretty smart. So he focuses on his strengths. Make of all that what you will.
Also, this is just a sidebar, but I always find it funny when I'm reminded that "Yankee" is Japanese slang. First because it's unintentionally more historically accurate than how Americans think about it: for us Yankee is just...us. Americans. But historically it was always used as a pejorative, either by the British or the South, and in both cases it meant "Those uncultured idiots." "Yankee Doodle" is all about the British accusing the Americans of being moronic, uncultured country simpletons playing at being sophisticated, and the South had largely the same feelings. And second, because outside the baseball team, we haven't used the word since the 1800s, so it's funny to see it crop up in modern times. I imagine a bit like if American youth started calling themselves "The Shoguns" (将軍).
Anyway, I hope that answers the questions, and good luck with the translation!
Oh, almost forgot-
IMPORTANT WARNING:
The ENTIRE TEXT of the first game is contained in Gutter Trash, for programming/game design reasons. Be careful, or you'll end up wasting time translating two games instead of one. I'll update this post later today with information on the best way to avoid this.
UPDATE: Most of the translation is dialogue, and most of the dialogue is stored in two places: the Mapxx.json files and CommonEvents.json. For the map files, start on 20. Everything before that is the first game. For CommonEvents, scroll down to id 50, or just search "GT Events Below". Everything before that is from the first game and can be ignored. Those two should save you from 90% of the extra work. You might end up translating an item or weapon from the first game, but there aren't many of those, so it won't waste much time.