RE: https://wp.box464.social/2009/11/20/post-2009-11-20t171124-0600/
Finally tested this - it is possible to export your Facebook posts directly from your Facebook account into an ActivityPub enabled Wordpress account - all with just click and point steps, no coding required.
They appear to be appropriately backdated. Came in as "Not Federated" so there WOULD be an additional step to federate them. I would NOT suggest doing this if you already have tons of followers - they will most likely get spammed.
More testing to come. Not sure if media gets ported over.