Huge kudos on this project -- I love this kind of thing. You sometimes see comments like "Why translate [console game] when it's already in English on PC?", but that overlooks the possibility of console-exclusive content or other cool stuff, or just having interesting differences. (Usually the person making such comments hasn't actually played the console version, but just assumes...)
As a side note, are you mainly interested in the Zork series specifically, or are you more broadly interested in projects that transfer English-language PC assets to leverage translation of console versions? The 3DO, Saturn, and PlayStation are absolutely loaded with opportunities for that kind of thing, and the 3DO in particular has a nice habit of storing its script files in plaintext.
Best of luck with it -- I'll be following your progress eagerly!