Okay, I've added "replaced by" and "replaces" information to these SRFIs on the home page, the final SRFIs page, and the home page (e.g.) and "README.org" page (e.g.) for each SRFI.  I've also document the terms "replaced by" and "replaces" in the FAQ (last item).  Finally, I've added links to the Status section of each affected SRFI document.  And the infrastructure supporting this allows multiple SRFIs to claim to replace any particular SRFI in case there are competing proposals.