Add and re-order Simple Social Icons, remove plugin css, add FontAwesome, add new styles (https://gist.github.com/carasmo/5a40a72ef6503e4545fc38a6933fab4a)

simple-social-for-functions.php

<?php

//* do not add this opening php tag above
//* this code is intended for your child theme's functions.php file or functions plugin
//* IMPORTANT: use a code editor and ftp to add code to your functions.php NOT the appearance editor
//* change yourprefix in the functions and handles
// see file https://gist.github.com/carasmo/5a40a72ef6503e4545fc38a6933fab4a for the css

/** ====================================================================================== 
 *
 * Remove Simple Social Icon Plugin Stylesheet
 *
======================================================================================= */

function yourprefix_remove_simple_social_icon_font() {	

	if ( ( ! class_exists( 'Simple_Social_Icons_Widget')  ) ) return;
	wp_dequeue_style( 'simple-social-icons-font');  
	
}
add_action( 'wp_enqueue_scripts', 'yourprefix_remove_simple_social_icon_font', 99 );



/** ====================================================================================== 
*
* Load Custom CSS for Simple Social Plugin
*
======================================================================================= */

function yourprefix_simple_social_css() {	
	
	if ( ( ! class_exists( 'Simple_Social_Icons_Widget')  ) ) return;
	
		$css_path = '/css/simple-social.css';
		//* assumes path of theme/css change to yours

		wp_enqueue_style( 'yourprefix-simple-social', CHILD_URL . $css_path, array(), CHILD_THEME_VERSION );  
		     	
}
add_action( 'wp_enqueue_scripts', 'yourprefix_simple_social_css' );



/** ====================================================================================== 
 *
 * Remove FontAwesome from all plugins
 * Install the latest version from CDN
 * Modified from: Dequeue Font Awesome plugin
 * Plugin URI: http://tiguandesign.com
 *
======================================================================================= */

function yourprefix_remove_font_awesome_from_other_plugins() {

	global $wp_styles;

		//* we'll use preg_match to find only the following patterns as exact matches, 
		//* to prevent other plugin stylesheets that contain font-awesome expression to be also dequeued
		$patterns = array(
			'font-awesome.css',
			'font-awesome.min.css'
		);

		//* multiple patterns hook
		$regex = '/(' .implode('|', $patterns) .')/i';

		foreach( $wp_styles -> registered as $registered ) {

			if( preg_match( $regex, $registered->src) ) {

				wp_dequeue_style( $registered->handle );

			} //* end preg_match
			
	} //* end foreach
	
	//* FA was dequeued, so here we need to enqueue it again from CDN
	wp_enqueue_style( 'yourprefix-font-awesome', '//maxcdn.bootstrapcdn.com/font-awesome/latest/css/font-awesome.min.css' );
	
}	
add_action( 'wp_enqueue_scripts', 'yourprefix_remove_font_awesome_from_other_plugins', 999 );


/** ======================================================================================
 *
 * Simple Social Icon fields
 *   
======================================================================================= */

function yourprefix_simple_social_default_fields() {

	if ( ( ! class_exists( 'Simple_Social_Icons_Widget')  ) ) return;

	$styles = array(
			'title'                  => '',
			'new_window'             => 0,
			'size'                   => 36,
			'border_radius'          => 50,
			'border_width'           => 0,
			'border_color'           => '#ffffff',
			'border_color_hover'     => '#ffffff',
			'icon_color'             => '#ffffff',
			'icon_color_hover'       => '#fc7070',
			'background_color'       => '#fc7070',
			'background_color_hover' => '#666666',
			'alignment'              => 'alignleft',
			
			//* reordered based on new order in 
			//* yourprefix_simple_social_default_profiles
			'rss'                    => '',
			'facebook'               => '',
			'twitter'                => '',
			'gplus'                  => '',
			'linkedin'               => '',
			'snapchat'               => '', //* added
			'email'                  => '',
			'bloglovin'              => '',
			'dribbble'               => '',
			'flickr'                 => '',
			'github'                 => '',
			'instagram' 	         => '',
			'pinterest'              => '',
			'stumbleupon'	         => '',
			'tumblr'                 => '',
			'vimeo'                  => '',
			'youtube'                => '',
		);
		
	return $styles;
		
}
add_filter( 'simple_social_default_styles', 'yourprefix_simple_social_default_fields' );


/** ======================================================================================
 *
 * Simple Social Icon $glyphs and $profiles
 *   
======================================================================================= */
function yourprefix_simple_social_default_profiles() {

	if ( ( ! class_exists( 'Simple_Social_Icons_Widget')  ) ) return;

	$glyphs = array(
			'rss'			=> '<span class="fa fa-rss" aria-hidden="true"></span>',
			'facebook'		=> '<span class="fa fa-facebook" aria-hidden="true"></span>',
			'twitter'		=> '<span class="fa fa-twitter" aria-hidden="true"></span>',
			'gplus'			=> '<span class="fa fa-google-plus" aria-hidden="true"></span>',
			'linkedin'		=> '<span class="fa fa-linkedin" aria-hidden="true"></span>',
			'snapchat'              => '<span class="fa fa-snapchat" aria-hidden="true"></span>', //* added
			'email'			=> '<span class="fa fa-envelope" aria-hidden="true"></span>',
			'bloglovin'		=> '<span class="fa fa-heart" aria-hidden="true"></span>',
			'dribbble'		=> '<span class="fa fa-dribbble" aria-hidden="true"></span>',
			'flickr'		=> '<span class="fa fa-flickr" aria-hidden="true"></span>',
			'github'		=> '<span class="fa fa-github" aria-hidden="true"></span>',
			'instagram'             => '<span class="fa fa-instagram" aria-hidden="true"></span>',
			'pinterest'		=> '<span class="fa fa-pinterest" aria-hidden="true"></span>',
			'stumbleupon'           => '<span class="fa fa-stumbleupon" aria-hidden="true"></span>',
			'tumblr'		=> '<span class="fa fa-tumblr" aria-hidden="true"></span>',
			'vimeo'			=> '<span class="fa fa-vimeo" aria-hidden="true"></span>',
			'youtube'		=> '<span class="fa fa-youtube" aria-hidden="true"></span>',
		);

	$profiles = array(
	
			'rss' => array(
				'label'   => __( 'RSS URI', 'ssiw' ),
				'pattern' => '<li class="social-rss"><a href="%s" %s>' . $glyphs['rss'] . '</a></li>',
			),
			'facebook' => array(
				'label'   => __( 'Facebook URI', 'ssiw' ),
				'pattern' => '<li class="social-facebook"><a href="%s" %s>' . $glyphs['facebook'] . '</a></li>',
			),
			'twitter' => array(
				'label'   => __( 'Twitter URI', 'ssiw' ),
				'pattern' => '<li class="social-twitter"><a href="%s" %s>' . $glyphs['twitter'] . '</a></li>',
			),
			'gplus' => array(
				'label'   => __( 'Google+ URI', 'ssiw' ),
				'pattern' => '<li class="social-gplus"><a href="%s" %s>' . $glyphs['gplus'] . '</a></li>',
			),
			'linkedin' => array(
				'label'   => __( 'Linkedin URI', 'ssiw' ),
				'pattern' => '<li class="social-linkedin"><a href="%s" %s>' . $glyphs['linkedin'] . '</a></li>',
			),
			'snapchat' => array(
				'label'   => __( 'SnapChat URI', 'ssiw' ),
				'pattern' => '<li class="social-snapchat"><a href="%s" %s>' . $glyphs['snapchat'] . '</a></li>', //*added
			),
			'email' => array(
				'label'   => __( 'Email URI', 'ssiw' ),
				'pattern' => '<li class="social-email"><a href="%s" %s>' . $glyphs['email'] . '</a></li>',
			),
			'bloglovin' => array(
				'label'   => __( 'Bloglovin URI', 'ssiw' ),
				'pattern' => '<li class="social-bloglovin"><a href="%s" %s>' . $glyphs['bloglovin'] . '</a></li>',
			),
			'dribbble' => array(
				'label'   => __( 'Dribbble URI', 'ssiw' ),
				'pattern' => '<li class="social-dribbble"><a href="%s" %s>' . $glyphs['dribbble'] . '</a></li>',
			),
			'flickr' => array(
				'label'   => __( 'Flickr URI', 'ssiw' ),
				'pattern' => '<li class="social-flickr"><a href="%s" %s>' . $glyphs['flickr'] . '</a></li>',
			),
			'github' => array(
				'label'   => __( 'GitHub URI', 'ssiw' ),
				'pattern' => '<li class="social-github"><a href="%s" %s>' . $glyphs['github'] . '</a></li>',
			),
			'instagram' => array(
				'label'   => __( 'Instagram URI', 'ssiw' ),
				'pattern' => '<li class="social-instagram"><a href="%s" %s>' . $glyphs['instagram'] . '</a></li>',
			),
			'pinterest' => array(
				'label'   => __( 'Pinterest URI', 'ssiw' ),
				'pattern' => '<li class="social-pinterest"><a href="%s" %s>' . $glyphs['pinterest'] . '</a></li>',
			),
			'stumbleupon' => array(
				'label'   => __( 'StumbleUpon URI', 'ssiw' ),
				'pattern' => '<li class="social-stumbleupon"><a href="%s" %s>' . $glyphs['stumbleupon'] . '</a></li>',
			),
			'tumblr' => array(
				'label'   => __( 'Tumblr URI', 'ssiw' ),
				'pattern' => '<li class="social-tumblr"><a href="%s" %s>' . $glyphs['tumblr'] . '</a></li>',
			),
			'vimeo' => array(
				'label'   => __( 'Vimeo URI', 'ssiw' ),
				'pattern' => '<li class="social-vimeo"><a href="%s" %s>' . $glyphs['vimeo'] . '</a></li>',
			),
			'youtube' => array(
				'label'   => __( 'YouTube URI', 'ssiw' ),
				'pattern' => '<li class="social-youtube"><a href="%s" %s>' . $glyphs['youtube'] . '</a></li>',
			),
		);
	return $profiles;
}
add_filter( 'simple_social_default_profiles', 'yourprefix_simple_social_default_profiles' );