WordPress routes with no backing content page: RFCodeReview

routes.php

<?php

/*

THE GOAL:
Programmatically specify routes critical to the successful functioning
of the application, without any requirement for pages to be set up that
use specific templates or have specific names

THIS APPROACH:
We have validated that this approach works even if the user makes a page
slugged e.g. `add-survey`: the custom template has been named so that the
regular template hierarchy will pick the right thing. In all other cases
(where no page e.g. `add-survey` is available), WordPress will 404, but
will still load the right template. We suppress the 404 status code with
the `status_header` function.

In instances where an appropriately titled page IS available, it could
be possible to pull in that page's content so as to permit user-edited
copy to be flowed into the page.

THE QUESTION:
Is this a "good" way to do this? Are there any obvious gotchas here?

We suspect that not using rewrites for these routes probably means we are
incurring extra DB queries that we then throw away; that inefficiency is
"acceptable" given the side-effect of enabling later content management
as per the second approach paragraph, above.
 */

/**
 * Load specific templates when specific URLs are requested, overriding WP's
 * internal page template hierarchy
 *
 * @param  {String} $template The template that WP expects to load
 * @return {String}           The path to the template WP will actually load
 */
function myproject_custom_routes( $template ) {
	$request_uri = $_SERVER[ 'REQUEST_URI' ];

	function myproject_custom_title( $page ) {
		// Expose the passed page title to the returned filter method via "use"
		return function( $original_title, $sep, $seplocation ) use ( $page ) {
			$site_title = get_bloginfo('name');
			return __( $page, 'myproject-efficiency' ) . " $sep $site_title";
		};
	}

	foreach ( array(
		'/survey/new' => array(
			'title' => 'Add Survey',
			'template' => 'page-add-survey.php'
		),
		'/surveys' => array(
			'title' => 'Survey Reporting Dashboard',
			'template' => 'page-dashboard-surveys.php'
		),
		'/timesheet/new' => array(
			'title' => 'Add Time Sheet',
			'template' => 'page-add-timesheet.php'
		),
		'/timesheets' => array(
			'title' => 'Time Tracking Dashboard',
			'template' => 'page-dashboard-timesheets.php'
		)
	) as $route=>$route_obj ) {
		if ( $request_uri == $route || $request_uri == $route . '/' ) {
			add_filter( 'wp_title', myproject_custom_title( $route_obj['title'] ), 10, 3 );
			status_header( 200 );
			return locate_template( array( $route_obj['template'] ) );
		}
	}

	return $template;
}
add_filter( 'template_include', 'myproject_custom_routes', 99 );

function myproject_rewrite_rules() {
	// Permit access to survey record "single" views by ID, not slug
	add_rewrite_rule(
		'^survey/([0-9]+)/?',
		'index.php?post_type=myproject_survey&p=$matches[1]',
		'top'
	);

	// Permit access to timesheet record "single" views by ID, not slug
	add_rewrite_rule(
		'^timesheet/([0-9]+)/?',
		'index.php?post_type=myproject_timesheet&p=$matches[1]',
		'top'
	);
}
add_action( 'init', 'myproject_rewrite_rules' );