Now you have changed the discussion from overdischarged to severely overdischarged [...] Remember this discussion involves a single cell driven down to around 1.2 volts.
Not at all. I am simply discussing the matter in general. Whether or not that overdischarge is "severe" in the OP's context depends on many factors which we don't know.
This paper goes into the difference. It is interesting to note that for these particular cells "The cells under overdischarge that were terminated in Stage I exhibited no discernible changes in properties..." Stage I involved discharging down to 0 volts.
Did you forget that it was I who originally mentioned that paper here and discussed it at length? I see nothing there that provides scientific evidence supporting your proposed overdischarge safety test. Nor am I aware of any other scientific literature that would prove such a test to be generally reliable.