Hope you are well! I just wanted to update you on the Commons app progress for WLM integration - we are (hopefully) close to being able to do a beta release. Currently the only two major items that we have yet to complete are attaching the appropriate templates to the files uploaded, and integration of country-specific property queries via the tool that we are collaborating with Stephen on.
To that end, we have a few questions:
Indeed, the template WLM is just here to indicate that a photo is taking part in WLM and in which country (and add corresponding categories).
For the identifier, each country/area use a different template (and sometimes several templates, in France we have two: Mérimée and Palissy)
2. How do we find the monument ID? Given that we are using Wikidata rather than the monument DB, is the Wikidata QID synonymous with the monument ID?
Usually the ID is given by the uploader. We have a specific field for that in the campaigns, by the way you can look at the code of the campaigns like https://commons.wikimedia.org/wiki/Campaign:wlm-fr
to know which template is use by each country (I thought there was a matching table somewhere but I can't find it back, maybe someone know what I thinking about).
Except for a very small number of countries (India and the template "WLM India Wikidata ID" is the only one I know), the Wikidata QID is not the same as the monument ID. But if you have the Wikidata QID you could probably easily find the monument ID via the API.
3. Is it possible to have a sandbox "monument" that we can use to test our implementation end-to-end, before WLM starts?
Probably but not sure, I'll let others answer that one.