As you mentioned, there are some pages in the
wiki such as the one about using
Reading Lists with FFF to sync devices.
I would also point out that it is a
wiki. Users can edit pages; not sure about adding new ones--but I certainly can do it for you on request.
As for custom columns, it seems to vary an astonishing amount from user to user what they each read, from what sites, and what they choose to track. Word count and Updated date are
probably universal, but that's about it, in my experience.
I suppose if there's interest, I could look into adding feature(s) that would let you click a button in FFF somewhere to add new custom columns for certain FFF metadata entries. But they'd be the 'standard' FFF metadata entries, not site specific ones like AO3's 'kudos'.