The bottom line is that whatever you do you must not force buyers to do anything beyond purchasing the file to use it and definitely not track it’s use.
Some authors are implementing automatic updates etc. that are triggered by buyers submitting their purchase codes and so on which is fine because it is voluntary.
That script looks like it license elements at a secondary level form buyers purchasing the the theme? This would not be allowed.
I am 110% behind preventing people abusing licenses etc. but it has to be done correctly. Check out this post when the likely reasons behind the rules were outlined.
Hope that makes sense,