Patched the go-webfinger library (https://github.com/writeas/go-webfinger) so it supports requests without the acct: scheme and that seems to make blogs discoverable on #Pleroma. Still needs more testing.
Blogs are now discoverable on #Pleroma, but following doesn't seem to work -- no request is made to Write.as -- and the URL to the blog isn't correct. Will keep picking away at it.