I just received this update from Posthaven’s developers . . .
We’re happy to announce Posthaven now supports multiple contributors per blog.
On your Posthaven dashboard in the settings for your site you will now find a “Contributors” tab where you can add and manage contributors. The owner of each email you add will be able create new posts on your site via email right away. They will also have the option to create a free contributor-only Posthaven account so that they can post via the web and edit their posts on your site.
Contributors who create an account and add a name to their profile will be listed on your blog and have their posts attributed to them. See this in action on our blog and on this post.
Learn more at the Posthaven blog.