This reminded me that the manual installing and uninstalling of the ACR plug-in is a trivial procedure. Amazing that there are posters having a hard time with such a simple thing.
On Windows the ACR 8.7 RC installer updated the Camera Raw.8bi file for PS-CS6, PS-CC, PS-CC-2014 with one run of the installer, rather than having to download and run separate installers for CS6 vs CC. In fact the installer URL is identical in the CS6 and CC branches at Adobe Labs, where the only difference is that the CS6 branch also includes the DNG Converter 8.7 RC, so they really could have been compbined into one ACR 8.7 group, now.
I’d think to roll back completely you’d also want to reinstall the DNG Converter 8.6 to get all the older color profiles, and if those could be the cause of your issues, then maybe copy them somewhere so you can put them back when you flip the camera raw plug-in file back to 8.7..
SS, you seem to have missed this in my Edit:
After troubleshooting my color issue, I determined it was being caused by an extreme, inadvertent setting of the Remove Fringe slider in ACR, so I went ahead and updated again to ACR 8.7.
Sorry for your troubles.