First of all the modified SCUMM scripts have to be finished. There are still some minor things to do IMHO (removing some of the "Throopweed" variations, maybe add logic to the sword fighting scenes that the proper response sample is chosen, ...)
If that is done, there is still some more work to be done, as the sword fighting scenes (and some other places) need a proper speech file assignment.
Finally the installer has to be finished to reduce the need of technical skills. I'm not sure how Espiox is coming forward with that.
For my very rough estimate, I guess it's about 5-8 man hours of work with some polish, maybe more. Translate that to the spare time everyone involved has for the project....
Of course anyone who wants to help out is welcome to do so. Alpha & beta testing is essential too....