In our case, the project is a new site, and a large percentage of our target audience have Facebook accounts. So we are seriously considering making Facebook logins a requirement for posting on our site. Obviously, this would not be an option for site owners with an existing forum, but it is an approach that new sites could consider. It really boils down to an assessment of whether the benefits of leveraging Facebook outweigh the downside of alienating some users.
Of course, many site owners (especially those with existing users) would not want to do something this Draconian. So I think it's a great idea to encourage interested parties to contribute ideas about a solution which would not require all posts to be made by a Facebook user.
In terms of the options you posted above, I have a question:
Usually when an external site posts something to Facebook, there is a "Comment" link on the message. Is this link mandatory? If it is mandatory, that's a problem, because the discussion will simply take place on Facebook. If it can be omitted, these solutions might indeed drive some traffic to EasyDiscuss, but not having a discussion take place on Facebook will significantly reduce the viral-potential of the Facebook post.
I will also continue mulling-over other options, and report back if I have any inspiration