Hi,
if you launch Superior 2 and you can load the libraries without getting any error messages, they are installed correctly.
There seems to be some kind of permission problem on your Sierra OS system (the other one works just fine, right?) when creating the MIDI libraries header.
Are you the Admin of the computer with full Admin rights? Are there several User accounts?
Is there an 'EZDrummer' folder in your 'Mac HD/Library/Application Support/' folder? If so, can you please post a screen shot of its contents? If it has a subfolder named 'Midi', please make sure you have full rights for it.
When you write that the Demo complained about an EZDrummer 1 license, I am a bit curious as to which installer file you ran - what was the file name?
And there's no need to speculate about the Superior line, it's not going anywhere.
BR,
John