@MelitaKennedy An issue that came up when I was working on the Geologic Mapping Template a long time ago at Esri has resurfaced. The issue had to do with providing a 'template geodatabase" that contained a feature dataset with a spatial reference of "Unknown Coordinate System" that would later be set by using the "Define Projection" tool. This was sometime around ArcGIS Desktop 9.3 or 10. I'm remembering this workflow was problematic, but I don't remember why.
Is there any way to refresh my memory as to why this workflow was problematic and/or if it's still problematic in ArcGIS Pro? My rough recollection is that the issue had something to do with the sort of "behind the scenes" math. Maybe with the Domain, Resolution and Tolerance values?