What’s the recommended process for organising collaborative posting?

The users over at the scifi/fantasy SE site are getting our blog organised. We definitely need:

• To know who is writing (or planning to write) about what.
• What stage (planning, writing, needs-editing, needs-scheduling, scheduled, posted) each post is in.
• Who is currently working on the post (writing, editing).

We started out with a Google Docs spreadsheet, but although this was very free-form, it (a) didn’t get well used, (b) doesn’t have any integration with WordPress, and (c) doesn’t have any notification system.

We recently switched to Trello (our board is here). There are a lot of features we like here:

• Transparency. Anyone (even people that aren’t writing for the blog) can see what posts there are, and where everything fits in the schedule. This is particularly important.
• It’s quite flexible (a lot of different metadata can be attached to a post).
• It’s easy to use and looks nice (which helps encourage people to use it).
• There’s no real-name requirement. If parts of the system are totally public (which we prefer) then this is a requirement. If the system is only visible to writers/editors then we can live with real names, although we’d prefer not to.
• Email addresses aren’t exposed. Email addresses are exposed in WordPress (unfortunately), so this also isn’t an issue for writers/editors, but we can’t have email addresses exposed to the general public.

However, there are things that aren’t so great:

• It’s yet-another-account. There’s a StackExchange account, a WordPress account, and a Trello account to manage. (This impacts on the real-name/email address issues from above, because an existing account may not be able to be used, and an email address is required to add an account).
• There are notifications, but there’s no documentation for them, so it’s not obvious how to use them or exactly what you get notified about.
• There’s no way to integrate with WordPress. This means that whenever a post changes status, it has to be updated in WordPress and Trello. This is made worse because as far as I can tell, WordPress doesn’t notify anyone when a post moves to “Pending” (so if the change is made only in WordPress, no-one notices).

We’re all new to collaborative blogging, but we know that other people have been doing this for ages. What’s the standard / best way of doing this sort of organisation?

If there’s a WordPress plug-in that we can use to do everything inside of WordPress itself, we can probably get the StackExchange staff to install that.

Alternatively, is there a third-party site that offers much/all of what Trello does, but integrates better with WordPress?