Adding a parameter to a custom post

I have found these parameters

/*
     * The $supports parameter describes what the post type supports
     */
    $supports = array(
        'title',        // Post title
        'editor',       // Post content
        'excerpt',      // Allows short description
        'author',       // Allows showing and choosing author
        'thumbnail',    // Allows feature images
        'trackbacks',   // Supports trackbacks
        'revisions',    // Shows autosaved version of the posts
        'custom-fields' // Supports by custom fields
    );

Instead of ‘author’ can I place ‘subscriber’? and can I display first name and last name of the subscribers? If the list of subscribers is long is it possible to place an autocomposer system?

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