If you have an M2.8 test server then please could you check Essential 188.8.131.52-RC2: https://github.com/gjb2048/moodle-theme_essential/releases/tag/V184.108.40.206-RC2
I'm progressively refactoring the code such that child theme support will be greatly improved and you'll be able to do cool things like supplying settings from the child theme to the slider rendering code to have different images without needing to override a single 'layout' or 'layout/include' file.
This release also fixes 'Issue #441: Messages Screen when on mobile ( - 767px ) - background not filling area (region-main).'.
Whilst I do test, with the complexity of Moodle, there is no substitute for 'in the field' testing. So please help me to help you .