Custom plugin not appearing

A few parameters need tweaking in midstory_fade_animation_script_register():

function midstory_fade_animation_script_register() {
    // Handle, script location, dependecies, version, in footer boolean
    wp_enqueue_script( 'midstory-animation-fade-block', plugin_dir_url( __FILE__ ) . '/midstory_animation_fade.js', array( 'wp-blocks', 'wp-i18n', 'wp-editor' ), '1.0.1', false );
}

• The script location needs a slash between the plugin folder and the filename.
• What you were calling “WordPress refresh?” is for a version number.

That will get your block showing up as an option to add in the Editor. Beyond that, you should look into wordpress/element rather than calling React directly as WordPress has built wrappers around its functionality.