1. The subs in the pack are mostly Chinese, so I thought I will keep it the same with the pack. 2. I can read both Chinese and English, but I think machine translation is more accurate for Chinese.Why machine translate to Chinese? Ultimately, the goal for most here is to translate to English. We have so many Chinese subs because they're the ones making subtitles, not so much Japanese, who have little need for them (perhaps aside from hearing impaired people).
Those aren't duplicates. They're different versions of subtitles for the same movie. If you check the sizes or content, you'll notice they'll all be slightly different. There's no way for my organizing software to judge quality, so as long as there's any difference in the files, I have to preserve them all.
Regarding duplicates, I had a look at the content but didn't see any difference, I will need to take a closer look later.