I think it would be sweet to understand the flow of data here. I was thinking about drawing a diagram. It goes like :

1. replication into the log file (just a big no-sql dump)
2. rust is told (via a graphql mutation) to nom some log into it's relational sql database, which currently looks something like :
   
3. rust provides a graphql interface which lets you ask a range of questions really easily of those sql tables.
4. ssb-patchql is an js plugin for the js ssb-server which just starts the rust binary up so steps (2) and (3) just work

@arj to answer your question, the sql tables have a lot of what you want. I think with a little reading / more documentation we'll see that links might be the backlinks you might want ... you can see there's an about table which gathering about messages. The only things that might need dong would be to expose some of this using graphql. Personally I'm keen to replace some core Patchbay stuff with this .... start with something simple like likes ... move on to names (which is a massive slow cached process at the moment).