Hello,

1. That option works when the Elementor or WPB is enabled on the site, also it does not turn off font awesome, just gives the ability to always have a connected font awesome on the page.

2. Yep, it works only with the WP Rocket plugin. In general, I suggest you read our article about site optimization: https://xtemos.com/wordpress-performance-optimization-the-ultimate-guide-in-2021/ , also you can see there all files that the “WP Rocket delay JS exclusions” option includes: https://take.ms/1nDKj

Kind Regards