Ken,
It definitely wasn't the first option that came to mind. This is also why I really love MAMP these days since I can play around, practice, make mistakes, etc., and not affect anyone . I'm not sure why these two are sort of stuck (well AMF I at least see there was an issue with that tracker) but this I can take care of it.
I'm hitting the end of cleaning up our Moodle site with LOTS of old stuff. In about 4 weeks I'll do everything for "real". I've gotten the site down from 60 additional plugins to 20-21, and from a peak size of 50Gb in Jan 2016 when I took it over to about 4.5Gb. What a difference a year makes, plus a whole lot of learning in between.
As far as Oauth2 goes, I did install it last year at some point to test it out but I'm not sure why it doesn't have the uninstall option. In any event, on their plugin page they mentioned that as of 3.3 it is moving into core Moodle so I'd like to take care of it sooner rather than later. There was a similar situation with User Tours moving to core Moodle as well and needed to remove the old first to make way for the new.
Hopefully I won't be having to do anything with plugins for sometime (other than routine updates). As you can see from the numbers above, it's been some major cleaning and I'm not keen to add stuff after inheriting years of bloat. As always, thanks for you help and thoughts!