Can a report be generated from Alfresco of all the documents on a Site, including the version number, to e.g. a csv file.
Or can a document's version be live referenced, to e.g. Confluence?
Without custom implementation or use of a 3rd-party addon, there is no report generation to list all documents of a site including their version number.
It is technically possible to reference a specific version of a document by using the technical NodeRef of the version node, but this is generally not supported / recommended for use in the UI (it mostly works with the out-of-the-box document details page, but any addon / customisation will likely not be implemented to work correctly with anything but the "most current" version).
Retrieving data ...