I’ve been investigating federating write.as with Lemmy a lightweight link-aggregator. One thing you would need to support is AcitivtyPub Groups which is what I’m putting in a request for.
Here’s the lemmy documentation. I spoke with @nutomic a full-time dev for the project who is interested in federation but this requirement would need to be met 1st.
https://join-lemmy.org/docs/en/federation/overview.html
I think it compliments lemmy nicely and could be used as a pseudo-wiki of sorts or when you need something different than the standard lemmy writing UI.