Modifying title of other widgets

There is the widget_title filter hook if that is what you had in mind?

I use the following in one of my themes:

/**
 * DMM Widget Title
 *
 * Fixes display issue when widget_title is empty by adding a space if it is.
 *
 * @package Desk_Mess_Mirrored
 * @since   2.0.1
 *
 * @param $title
 *
 * @return string
 */
function dmm_widget_title( $title ) {
    if ( '' == $title ) {
        return ' ';
    } else {
        return $title;
    } /** End if - title is null */

} /** End function - widget title */
add_filter( 'widget_title', 'dmm_widget_title', 10, 1 );

Not sure if will help but it is a working example.