Under which NPO will the project be ran, if at all? From the description (which isn't much) in the first post, it looks like you maybe have not dealt with anything like this before.

I would urge anyone, generous as volunteering is, to err on the side of caution. It does seem strange that you're looking for a few craftsmen (and a project manager; all of whom become equal partners) and nothing else related to such a project. To anyone interested, ask lots of hard questions and don't drop your guard just because this is work for a "non profit project".