After considerable time trying to fix this, I’ve come up with what I think is a solution:
I think some of my OS installs may have gotten somewhat corrupted; I haven’t figured out how to check this, but the reason I believe this is that some of the issues were randomly corrected after I was forced to install a fresh version of the OS after a power outage corrupted the image I was using. This IS after I had tried several different OSs so…who knows?
Also, right now, I’ve SMB1 turned off and I can access the PI. I’ve tried a TON of different searches but what eventually worked is captured here:
https://community.spiceworks.com/topic/1995592-disabling-smb1-stops-domain-authentication?page=1
Now, I’m just going to go figure out how to get the USB drive to work with this whole situation.