User that Admin can Post As, but Who Cannot Themselves Post

I have a site that is in some form a directory of restaurants and content that we, the admins put up for each restaurant to promote them. Each restaurant is an author on the page, but we do not give the actual client (restaurant owner) the login info. We don’t want them to be able to log in and post their content themselves.

But now we are using the Upload Widget plugin, which creates a widget to upload a file, but only to the user role you specify. We would like our clients to be able to upload a video to us, for us to post as them, but only if they’re logged in. The problem is – that then requires us to give them login info, which would give them way too much access in our site as Authors. Is there a way to set up a role for them that they can log in, and I could set the widget to allow them to upload, but they can’t post? The catch to this is that we still need to be able, as Admin, to post AS them. So a user who can’t post when logged in, but who the Admin could post as.

Sorry if this is confusing. Any ideas?

Thanks!