I think the answer is "no" to all of Matthew's questions ... unfortunately.  The original Annotea group has wound up.  Ralph Swick is still with W3C, but no longer interested in in Annotea. I had a short conversation with Ivan Herman a few weeks back (face to face!) and the impression I got was that he thinks that Annotea is out-dated.  Anyway, he said that there was little chance that the W3C Semantic Web group would reactivate this area.  Another possiblity is /Marja-Riitta Koivunen/ and her "annotea.org" website.  However, the indications are that she is semi-retired at the moment: there have been no updates to the site since 2006 and she didn't respond to my email.

So I think the most practical solution would be to set up an informal working group (independent of W3C) to come up with consensus answers and document them.  A Wiki-based group sounds a reasonable approach.  (We might be able to host an Annotea Wiki on "http://metadata.net" ... I need to check out some issues.)