So I updated the plugin, and tried to get a new shortcode in Settings. It told me I needed a page ID. I went to Facebook Options.
Though I already had an Access Code, I suspected I needed to go through that. I selected the button to request an access code.
I got a page asking me to log in – my personal self, saying nothing about the page I manage. I did, and was asked if I wanted SlickRemix to “manage my Facebook pages.” Hell no.
Back on Facebook options, I tried to get a new Facebook ID. I was told
“Click on a page in the list below and it will add the Page ID and Access Token above, then click save.”
There were no pages in “the list below.”
The shortcode page still wanted me to supply a Facebook Page ID.
I have rolled back the plugin again, and guess I will just leave it that way.