It works, not seamlessly but close. Any community is considered to be an account, with any posts made to it considered to be a "tweet". Any comments are replies to the post. A microblog account can post to a community by @ ing it, and reply to comments and posts by... replying to the post.

From lemmy to microfedi doesn't work as well, but you can reply to posts as normal and like by upvoting.

idk, maybe like a server for "-key"-derivates with a community for each individual derivate?

Some of these derivates will be hugh, but reddit-like sites can already deal with communities of vastly different sizes, so whatever i guess.