Can the results of a query in documentList be reused inside the function?

Can the results of a query in

documentList

be reused inside the function? For example, I’d like the title here to say like “13 Properties with Inspection Times” or whatever the count of the query is…

That’s not possible at the moment. But since you can run promises/observables, you can do the query in the structure builder… structure and use the data where you need it.
Here’s an example where we fetch counts in the icons:
https://sanity-io.slack.com/archives/CGKNRPC80/p1593460636120200?thread_ts=1593460050.120000&cid=CGKNRPC80
And another where we use the documentstore to list out tickets by their tags (that can be adapted to your use case):
https://github.com/sanity-io/community-studio/blob/master/deskStructure.js#L143

That’s not possible at the moment. But since you can run promises/observables, you can do the query in the structure builder… structure and use the data where you need it.
Here’s an example where we fetch counts in the icons:
https://sanity-io.slack.com/archives/CGKNRPC80/p1593460636120200?thread_ts=1593460050.120000&cid=CGKNRPC80
And another where we use the documentstore to list out tickets by their tags (that can be adapted to your use case):
https://github.com/sanity-io/community-studio/blob/master/deskStructure.js#L143

Okay cool. Yeah after posting I figured maybe I could do the query elsewhere and pass in the results that way. These code examples help, thanks!