Re: whatever happened to these characters?
They do appear in A Singular Destiny
and Gomez and one other character who I can't remember right now, make brief appearances in Indistinguishable From Magic
(although this is apparently no longer part of the novelverse continuity).
They say a little knowledge is a dangerous thing, but it is not one half so bad as a lot of ignorance. - Terry Pratchett, Equal Rites