@smallcircles @andy Thanks for the links! Super interesting discussions, definitely makes me wonder about alternative approaches.
Conversely, after thinking about it...maybe the document method is not so limiting? If you have an app that has some kind of listener to check changes inside of a container, it might be possible to translate things done within a Solid Pod (Create, Update, Delete) to activities dispatched from an ActivityPub Outbox.
The biggest thing is that you'd still have to reconcile WebID identities to also be ActivityPub actors, and provide inbox / outbox methods.