Wouldn't it be great if there were concrete best practices to guide the stewardship of GIS address point layers? And what if they were flexible and also provided guidance for complex situations like multi-unit buildings and campuses were included?

That's exactly what you'll find in the NENA Information Document for Development of Site/Structure Address Point GIS Data for 9-1-1 which was approved for publication on 9/18/2015. If you're involved in addressing or you want to see a great example of a best practices document with lots of examples, give it a whirl. The technical detail begins in section 3.