Yes, the link was what I followed.
In any case, I realized that I needed to add domain as part of user (USER@ABC.edu rather than USER which is used in browsers) and it is now working!
[odrive-webdav]
type = webdav
url = https://ABC.sharepoint.com/sites/XYZ/Shared Documents
vendor = sharepoint
user = USER@DEF.edu
pass = REMOVED
Regarding adding this remote as OneDrive, neither Option 3 or 4 works (log in my original post). @ncw It would be nice if this is possible so that we don't need to use username/password to authenticate. Since I can add SharePoint sites from my domain as OneDrive, I took this to mean that the organization did not have this issue?