OK, trying to do some of my own homework to see if this path is viable. I gather the Bluechart maps in the links provided ARE the "real" Garmin maps? I may be getting ahead of myself but if I could plead for a brief explanation of what these 5 possible NA maps are, I think that would answer my questions. Enough that I can dig in and learn the process if applicable:

City Navigator North America NT 2017.10
Garmin City Navigator North America NT 2015.40
City Navigator North America 2009 MapSource (NON-NT)
Approach CourseView Americas
OSM based North America Maps for Garmin fenix

And, thank you for what appears to be a good alternative Neil