The problem with hacking the subtitles is, well, as you stated here, that the number of characters available for any given text block is extremely limited. For example, in the Japanese text you have provided here, the English translation would be "Dance, run away, make noise." That's 28 characters. "Dance, run, sing" is still 13 characters, two characters too long, and there are very few text blocks which could be condensed in this manner. That makes a translation of, say, the software tests impossible because many of the questions and responses require that the reader comprehend the question, which is impossible if the Japanese is, say, 「CPUの説明で正しいものを選べ」 since the translation is ”What is the function of the CPU?”, 15 characters vs 31 characters, and no way to condense the question without making it incomprehensible.
So, although I like the idea of having Engllish subtitles, I don’t so much like the idea of butchering the language to make it work. If you happen to find a way around this limitation, I would be glad to help.
NumberTwo