Does the Golf multi-sco example represent the required set of schema definitions? Or is there room for differences? For instance, I noticed that the imsmanifest omits the URIs for adlseq, adlnav and imss. I also noticed some different .xsd files in the Strict folder, than in the Golf example. Can I depend on the Golf example to show the requirements? Or should I be referencing another document?
There really isn't a well defined requirement around the XSD files that need to be included and referenced. The requirement is that the XML is well-formed and that the elements that are used adhere to the published schemas. Our interpretation is that if optional elements (like sequencing or metadata) aren't used, then those XSD files can be legitimately excluded.
From a pragmatic perspective however, we typically just include the full set of XSD files in all published content. Instead of trying to figure out the minimal required set of XSD files, we find it much easier to just copy over and reference the full set. There minimal cost of a few extra files seems a worthwhile price to pay for simplicity.
Of course, the most important thing is to ensure that whatever you publish passes the SCORM Test Suites and is compatible with LMS systems. In our experience, simply ensuring valid XML is the most important factor here.
We publish a reference page that contains the authoritative XSDs for each version of the standard. That is where I would go to download a common set of files.