I finally got the mess resolved and repaired (see the link in reply #8 for the logs/history). I was aware that Safe Mode had limited features as you noted, but I wasn't sure whether Avast was/is accessible or not. I guess I should have rephrased it.
So just to confirm for the future, is there or is there not a way to start it manually in Safe Mode? Either with a command prompt or the Windows Taskbar?
Thank you.