Hi Molly,
I've edited a few things (ex. authority control metadata)
I think we should really double check that we mapped all the metadata
from template:book and Wikisource Index, as well as Wikidata properties.
I once did this:
(moreover, do you plan the metadata to be Dublin Core? Do you plan them to be optional and repeatable?)
In addition, I would integrate the work of Tpt with the OAI-PMH feed, which I assume it would be managed by your extension.
(maybe you already thought all of this, in that case sorry if I missed :-)
Aubrey