I think there are a few different things at play:
That’s my experience from working more than half a decade on Scala. It might provide some insight why the project is hemorrhaging contributors who cared about quality and user experience (apart from the harassment issues).
It is unclear which project you refer to, when speaking about hemorrhaging contributors, is it Linux or Scala?
How would this work in practice? User 1 is invited to Lobsters and the account becomes available on the other instances but without posting permissions? would the postings of that account within the whole tank become visible?
Personally, I would think just promoting each other in some header bar (but don’t make it a dickbar) to begin with.
If you look at brand book, you’ll see the gopher there.