I sincerely want to thank you for your help! This project took six-months and your assistance was crucial in getting over the goal line in the final week. If I missed that hard deadline my six-month contract-to-hire would have been terminated. Partly because of your assistance I made it work and was hired full-time permanent! We shipped Version 1.0 and two weeks later I delivered a significant V1.1 follow up!.
I momentarily had it setup as a (static?)linked library but backtracked to direct #includes from the /common/ folder, mainly because I understood it better. I intend to switch again to the library method because of compile times as you suggested. I was also scared off by an article suggesting I would need to add C++ #EXTERN statements, etc. to create a public interface for the library. Is that true, or can the .pro/.pri files define that folder as a library with NO changes to the C++?
I still have to migrate *.qml files to the /common/ but I assume it's basically the same pattern as the C++. I haven't replied because I thought I had more questions but the project has been moving too rapidly.