I am happy that you have tested the plugin and posted the results. It will also help you to test other free and premium themes.
Is that ok? Or shall I fix something?
Short answer is – It is Perfect
Theme Check result should not throw any REQUIRED output. If theme check result is free from REQUIRED output, than the theme is perfect and according to WordPress coding standards.
Same as REQUIRED. There should not be WARNING output by Theme Check plugin.
In your case, Theme Check has detected an error_log file by PHP. Find this file and delete it.
* This file is not the part of our Theme Package
No need to worry,
Screenshot size should be 880×660: This rule has been added recently after the launch of WordPress 3.8. So we will update theme screenshot in the next version.
No need to worry.