This comment is from my own blog! I’m using the #ActivityPub plugin as the main driver of federation, with the other main IndieWeb plugins (webmention, syndication links, post kinds, etc) to fill in the gaps to bring back comments from elsewhere, incl. Mastodon, and to reply to posts/toots. The Friends plugin acts as a feed function and a way to add people, though it’s not perfect and it doesn’t work for discovery of new content.
With all of these, I’ve been able to implement lightweight federation, though there is room for improvement.