Yes, syncing is on and working, so that's not the problem. (Though it is something people may often miss if they've turned of sync or paused it.)
Apparently there's no in-app panel for extensions anymore. I hadn't realized this, so when I had trouble installing the updated panel, which required installing an updated Extension Manger (which may have installed, but didn't communicate with the out of date panel), I figured I was in a deep hole filled with bugs.
Turns out, there is no panel for CC now, so none of the above was necessary. The CC Extension Manager is installed and working, and now that I understand it no longer has to communicate with some (nonexistent) panel in Illy, I think there's no problem remaining.
I'll grab a few CC-specific extensions and see how they fly. I suspect everything will work.
Thanks for the input. FYI, the "Another way" link you provided seems to be for CS6 only, so it wasn't applicable to my particular confusion.
Allen