does CCK help my module add custom fields

The APIs to create fields programmatically are located in includes/content.crud.inc. You may want to look at how the Content Copy module works (import/export content types with CCK fields and field groups). One module that I know of that provides a custom content type that needs to be imported is APK.

You may also want to look at the modules repository for a lot of CCK field implementation that extend those provided by CCK itself.

The CCK project page contains a few links to documentation to get started, also install the Advanced Help module. It provides a lot of information about CCK itself, Views, and other modules.

Re: "I am simply trying to create a module which ADDS numerous custom fields to any existing node type that i set it to."

Yes, you can.

See includes/content.crud.inc. Note that CRUD means Create Read Update Delete, field instances in this case. ;-)

If you look at the code in import function of Content Copy module, you'll see it uses CRUD methods to perform the task.

Another example. This is a snippet from Node Relationships module:

/**
 * Create a back reference field.
 *
 * @param $field_options
 *   An array with the following elements:
 *   - type_name       The content type where the is about to be created.
 *   - field_name      The name of the new field.
 *   - label           The label of the new field.
 *   - referrer_type   The referrer content type.
 *   - referrer_field  The name of the nodereference field in the referrer type.
 */
function noderelationships_cck_backref_create($field_options) {
  // Load the Create/Read/Update/Delete library for CCK objects.
  module_load_include('inc', 'content', 'includes/content.crud');

  // Build the field structure.
  $field = array(
    'label' => $field_options['label'],
    'field_name' => $field_options['field_name'],
    'type_name' => $field_options['type_name'],
    'type' => 'noderelationships_backref',
    'widget_type' => 'noderelationships_backref',
    'module' => 'noderelationships',
    'widget_module' => 'noderelationships',
    'required' => 0,
    'multiple' => 0,
    'description' => '',
    'default_value' => NULL,
    'default_value_php' => NULL,
    'default_value_widget' => NULL,
    'columns' => array(),
    'weight' => noderelationships_get_element_weight($field_options['type_name']),
    // Global field settings.
    'referrer_type' => $field_options['referrer_type'],
    'referrer_field' => $field_options['referrer_field'],
  );

  // Create the field.
  content_field_instance_create($field, FALSE);
}

/**
 * Delete a back reference field.
 */
function noderelationships_cck_backref_delete($type_name, $field_name) {
  // Load the Create/Read/Update/Delete library for CCK objects.
  module_load_include('inc', 'content', 'includes/content.crud');

  // Make sure the field exists and it belongs to us.
  $read_params = array(
    'field_name' => $field_name,
    'type_name' => $type_name,
    'widget_module' => 'noderelationships',
  );
  $instances = content_field_instance_read($read_params, TRUE);
  if (!empty($instances)) {
    content_field_instance_delete($field_name, $type_name, FALSE);
  }
}

Note how it uses content_field_instance_create(), content_field_instance_read() and content_field_instance_delete().

These methods allow you to manage existing implementations of CCK fields in content types.

If you need a CCK field that is not implemented elsewhere, then you need to implement it yourself, of course. For this, look at how other CCK fields are implemented. Start with simple fields such as Text or Number.