is there a way to get all queued scripts/styles into a template without `get_header()`?

the_header() does not even seem to be native WP function? Technically getting header isn’t what really causes styles and scripts to load, it’s wp_head() call that should be made there (and wp_footer() call in footer). So they are likely what you should be using. If you do need something lower level you might want to … Read more

Function to load correct CSS for Template not working

I think your big problem here is your use of underscores (_) in your page template names. According to the Handbook of Coding Standards Files should be named descriptively using lowercase letters. Hyphens should separate words. my-plugin-name.php Also, for best practices you should call your custom page templates page-whatever.php So for instance, index_page.php should be … Read more

Check for Twitter Bootstrap Loaded

There is no good way of doing this. One way is to enumerate the already registered scripts, like this: function yourplugin_add_my_stylesheet() { global $wp_styles; if ( $wp_styles instanceof WP_Styles ) { // enumerate all current styles foreach( $wp_styles->queue as $handle ) { // use the $handle to see if it’s called ‘bootstrap’ $obj = $wp_styles->registered[$handle]; … Read more

Understanding wp_enqueue_style

Scripts and styles get output with wp_head and wp_footer functions. If you enqueue a style after wp_head, it will be output in wp_footer, which, while in practice will often work, means the theme’s html will not validate. It’s up to you (or whomever is building a theme/plugin) to enqueue styles early enough to be output … Read more

FullCalendar in WordPress is not working

You page is generating two errors: Uncaught TypeError: undefined is not a function. This is likely due to the fact that WordPress sets jQuery to NoConflict mode. Your script is using the $ shortcut and is failing. Modify your script accordingly, either replacing the shortcut or wrapping the jQuery. https://codex.wordpress.org/Function_Reference/wp_enqueue_script#jQuery_noConflict_Wrappers

Deregister scripts from plugin

There’s a much better and more reliable way than naming your plugin “ZZ” – use a delayed hook on plugins_loaded, which fires after all plugins are loaded: function wpse_191178_plugins_loaded() { // Do your stuff } add_action( ‘plugins_loaded’, ‘wpse_191178_plugins_loaded’, 100 );