Update!
I found the solution by focusing on the "updates have been suppressed by administrator" angle since I should have been able to update from the direct links. Which lead me to a this thread: Re: adobe application manager fails to update
And the solution that finally worked for me was: to delete or rename the <Startup Disk>/Library/Application Support/Adobe/AAMUpdaterInventory/1.0/AdobeUpdaterAdminPrefs.dat
There was a huge backlog of updates, not just Premiere, that came through.