render Visual Composer shortcodes onto page

Use the:

WPBMap::addAllMappedShortcodes();

then as usual do_shortcode($content);

In short, page builder due to performance doesn't register shortcodes unless it isn't required.

If your element is registered by vc_map or vc_lean_map then no need to use add_shortcode function, you can do everything just by using WPBMap::addAllMappedShortcodes(); it is will call an shortcode class callback during the rendering process and then shortcode template.

Regarding Method 2.

You have to use do_shortcode() in your shortcode function.

function someshortocode_callback( $atts = array(), $content = null ) {    $output = '[vc_section full_width="stretch_row" css=".vc_custom_1499155244783{padding-top: 8vh !important;padding-bottom: 5vh !important;background-color: #f7f7f7 !important;}"][vc_row 0=""][vc_column offset="vc_col-lg-offset-3 vc_col-lg-6 vc_col-md-offset-3 vc_col-md-6"]column text[/vc_column][/vc_row][/vc_section]';    return do_shortcode( $output );}add_shortcode( 'someshortocode', 'someshortocode_callback' );

Working example on my test site: http://test.kagg.eu/46083958-2/

Page contains only [someshortocode]. Code above is added to functions.php.

In your code for Method 2 there is another error: line

echo add_shortcode('someshortocode', 'someshortocode_callback');

cannot work, as add_shortcode() returns nothing. This code should be as follows:

<?php $post = get_post();if ( $post && preg_match( '/vc_row/', $post->post_content ) ) {// Visual composer works on current page/post    wc_print_notice('VC ON', 'notice');} else {    wc_print_notice('VC OFF', 'notice');    add_shortcode('someshortocode', 'someshortocode_callback');    echo do_shortcode('[someshortocode]');}; ?>