GFCI outlet issue: downstream tests wired OK but upstream will not reset
Well, this is certainly full of red herrings, isn't it?  

Sounds like a disconnected neutral wire somewhere

"Hot Ground Reverse" is how a "magic 8-ball tester" tells you the neutral wire is not connected back to the panel, but a load is plugged in and switched on.  

So check each of the outlets in the string to see if they actually work.   The trouble will be either at the last working one, or the first defective one.  

The usual culprit is backstab connections. 

Here's what's really going on inside those magic 8-ball testers. 



The printed legends, however, are notoriously wrong and misleading.  This one has a more useful legend: