BuddyPress.org

The bundled version of jQuery in WordPress is different than the stock jQuery library.

WP adds a jQuery.noConflict() call. Most WordPress plugins rely on the WP version of jQuery. So by getting rid of the WP one, you’re going to be breaking some plugins.

I’m pretty sure WP has jquery-ui in their includes folder.

Check out this nifty codex article on wp_enqueue_script() to call a specific, bundled JS:
https://codex.wordpress.org/Function_Reference/wp_enqueue_script