I've been running fediverse as the commenting system on this blog for a while now. Here's how it's been going.

For the problem of linking back to your instance, I wonder if it would make sense to define a new URI scheme for fediverse links. Websites and apps can handle it directly when a user is logged in, or let an external app handle it otherwise.

a browser extension should also be able to handle them

Part of me says some sort of meta tag in the page header might be better, defining what sort of activity this is, and then users install browser extensions made by the fediverse apps they use to interact with them. That way if a non-fediverse user clicks the link, they can still access whatever it is. But a fediverse user would get a prompt like "Open this (thread/user/hashtag) on your own instance so you can interact with it?" Or they could set the extension to just do that automaticly for them.