Remove/unset options field from backend Settings->General?

Unfortunately, the html for those fields is hard-coded into the wp-admin/options-general.php file and there are no filters to keep them from being displayed.

The next-best thing is probably to disable them. Here’s how I’d approach it:

Step 1: Adding a bit of js/jQuery to the general options page that will target the inputs/selects you want to disable and add the disabled attribute to them.

PHP:

add_action( 'admin_enqueue_scripts', 'wpse_maybe_add_custom_disable_fields_js' );
function wpse_maybe_add_custom_disable_fields_js() {
    if ( 'options-general' == get_current_screen()->id && is_multisite() && ! current_user_can( 'manage_network_options' ) ) {
        wp_enqueue_script( 'wpse_custom_disable_fields', 'path/to/disabler_script.js', array( 'jquery' ), false, true );
    }
}

Where in the above you replace ‘path/to/disabler_script.js` with the correct path to the following file:

JS:

(function ($) {
    var fieldsIds = [
        'blogdescription',
        'WPLANG',
        'timezone_string',
        'date_format_custom_radio',
        'date_format_custom',
        'time_format_custom_radio',
        'time_format_custom',
        'start_of_week'
    ];

    $(document).ready(function () {
        fieldsIds.forEach(function (el) {
            $('#' + el).attr('disabled', 'disabled');
        });

        var radios = $('input[name="date_format"], input[name="time_format"]');
        $.each(radios, function (index, el ) {
            $(el).attr('disabled', 'diabled');
        });

    });
})(jQuery);

So far, we’ve made it hard for a “creative” admin to enter things into those fields, but they still could hack it into the browser. So, Step 2, we need to tie things down on the server end. Here, WP gives us a little help, because those setttings are all white-listed in the options processing, and we do have a filter to un-whitelist them:

PHP:

add_filter( 'whitelist_options', 'wpse_maybe_remove_settings_from_whitelist' );
function wpse_maybe_remove_settings_from_whitelist( array $whitelist_options ) {
    if ( is_multisite() && ! current_user_can( 'manage_network_options' ) ) {
        $whitelist_options['general'] = array( 'blogname', 'new_admin_email' );
    }
    return $whitelist_options;
}

Now, when the general settings form is returned, only the whitelisted options will be processed, even when other options have been hacked in and submitted.