Remove the first and last name fields from the EDD checkout.

edd-name-fields-be-gone.php

<?php

function pw_edd_remove_names() {
  remove_action( 'edd_purchase_form_after_user_info', 'edd_user_info_fields' );
}
add_action( 'init', 'pw_edd_remove_names' );

function pw_edd_user_info_fields() {
	if( is_user_logged_in() ) :
		$user_data = get_userdata( get_current_user_id() );
	endif;
	?>
	<fieldset id="edd_checkout_user_info">
		<legend><?php echo apply_filters( 'edd_checkout_personal_info_text', __('Personal Info', 'edd') ); ?></legend>
		<?php do_action( 'edd_purchase_form_before_email' ); ?>
		<p id="edd-email-wrap">
			<input class="edd-input required" type="email" name="edd_email" placeholder="<?php _e('Email address', 'edd'); ?>" id="edd-email" value="<?php echo is_user_logged_in() ? $user_data->user_email : ''; ?>"/>
			<label class="edd-label" for="edd-email"><?php _e('Email Address', 'edd'); ?></label>
		</p>
		<?php do_action( 'edd_purchase_form_after_email' ); ?>
		<?php do_action( 'edd_purchase_form_user_info' ); ?>
	</fieldset>
	<?php
}
add_action( 'edd_purchase_form_after_user_info', 'pw_edd_user_info_fields' );

How to remove or change following title: