This screenshot is what I was trying to do:
I was hoping for the bookmark icon to always appear alongside any other matching rules (mainly the reading list one, because the others indicate errors or metadata that needs changing). It doesn't appear though.
I understand how composed icons work now though. I kind of got my desired results by setting both bookmark and readinglist to composed and moving them to the start.

Once I figure out the template language I might be able to do something with the advanced rules.