So, I have to believe the reinstall process solved my issue. But, what about the addon namager issue?
There's no "issue", if you got that message, it means you have to update the Addon Manager (that's a GSX major update notification), but that doesn't necessarily mean something wouldn't work if you don't update it, just that you don't have the very latest version of it.
Or, more precisely, you surely have the very latest version of the crucial files that must be updated otherwise something won't work, because they are being downloaded by the installers, but you are still missing some additional files that are only available in the Stand-Alone Addon Manager installer.
As the message says, download and install the latest Stand-Alone Addon Manager.