Default some PMPro fields based on other user meta.

get_user_metadata_pmpro_prepop.php

/*
	Default some PMPro fields based on other user meta.
	
	Add this code to your active theme's functions.php or a custom plugin.
*/
function get_user_metadata_pmpro_prepop($value, $user_id, $meta_key, $single)
{	
	//fields to sync, make sure there are no loops in this
	$sync_fields = array(
		"pmpro_bfirstname" => "first_name",
		"pmpro_blastname" => "last_name",
		"pmpro_baddress1" => "address",
		"pmpro_bphone" => "telephone"
	);
	
	//is this a field we try to sync?
	if(!empty($sync_fields[$meta_key]))
	{
		//get the actual meta field
		$meta_cache = wp_cache_get($user_id, 'user_meta');
		if ( !$meta_cache ) {
			$meta_cache = update_meta_cache( 'user', array( $user_id ) );
			$meta_cache = $meta_cache[$user_id];
		}
		
		//only lookup the other value if the meta field is empty
		if(empty($meta_cache[$meta_key]))
		{
			$value = get_user_meta($user_id, $sync_fields[$meta_key], $single);
		}
	}

	return $value;
}
add_filter('get_user_metadata', 'get_user_metadata_pmpro_prepop', 10, 4);

This recipe is included in the blog post on "Pre-populate User Meta Fields with Membership Checkout Information" at Paid Memberships Pro here: https://www.paidmembershipspro.com/pre-populate-user-meta-fields-with-membership-checkout-information/