How to add Theme Customizer Color?

You’ve got duplicate control IDs:

$wp_customize->add_control( new WP_Customize_Color_Control( $wp_customize, 'link_color', array(

And:

$wp_customize->add_control( new WP_Customize_Color_Control( $wp_customize, 'link_color', array(

They’re both link_color, but they need unique IDs. Simplest option is to use the setting IDs:

$wp_customize->add_control( new WP_Customize_Color_Control( $wp_customize, 'starter_new_setting_name', array(

And:

$wp_customize->add_control( new WP_Customize_Color_Control( $wp_customize, 'starter_new_setting_name2', array(