Someone created that HFE (header-footer-elementor) to automatically support 4-5 themes/frameworks.
You are using one of his methods hfe_render_header() to render the Elementor's header, but that method is not defined in your functions.php.
To support it on Beans or any other theme, it needs a bit of customization and remove the unneccesary code that HFE is using to support other frameworks.
I never used Elementor or any Page Builders before, I am creating a theme myself, and i plan to support Elementor in the upcoming days. Once i will support it, i will share the code here.
Hi Joseph! Thank you very much! It is very nice to hear that you plan to support it in near future!