Progress report: There has been progress. I can extract the Japanese text into a script format that works for me at least, I've got a running Reference file because inconsistently Romanized proper nouns drive me absolutely bugfuck, and I can translate it. It's even a pretty good translation.
But pretty good isn't good enough. I'm basically on a translation equivalent of the last mile problem. If I can get over the wall that separates "this is well translated but it was obviously originally written in Japanese" and "this is natural English dialog", I'll be there.
The work continues.