If a directory is a PR5, and you submit to a page such as sitename.com/autos/services/repairs, and that particular page has PR0 - would you consider this entire directory submission to be a backlink from a PR0 page? This is something I never fully understood
I would consider it as PR0. The page might get more rank in time so it could help. So why not add a link as long as it is not a no follow or redirect.