Perhaps you should contact the K4 folks.
Okay, I am back up and running with fully functional InDesign for both workflows.
I ended up reinstalling the program. I was able to preserve my preferences upon uninstall without it affecting anything. After reinstall, my K4 plugins remained, and the InCopy plugins were restored.
I created a set in Extension Manager to facilitate switching between the two workflows.
I blame the script, but I can't rule out that I may have manually deleted the InCopy plugins. I was getting a lot of pop ups when I launched the program, and it was confusing. Hard to believe I wouldn't have saved a copy of that plugin folder somewhere, but it's possible; I just wanted to get K4 running and I didn't realize it would conflict with the InCopy workflow and related plugins, panels, etc.
Hopefully this will be helpful information for future reference.
Thanks for the update.