Membership item with custom fields

I am trying to implement a membership item that contains custom fields, so that that a single item purchased specifies the name and contact information associated with the member. I would like to make it possible for a user to purchase more that one membership per order but retain the information for each membership purchased (i.e. memberships for other family members on the same order).
I have two questions:
- I purchased Hikashop Essential but do I need the Business version to implement the fields?
- Where can you set the quantity of an item so that it only allows one item at a time? The parameter "Maximum quantity per order" does not seem appropriate.

As I understand it the option "Display the quantity field on the product page" to "no input" applies to the entire shop, so this will force all other items to be ordered the same way.
Is there another approach that would allow this to be set on a per item basis?

Also the option "Display the quantity field on the product page" to "no input" does not seem to affect the checkout screen that shows a quantity box that can be incremented.

This is disappointing, I will have to use Virtuemart instead of Hikashop, which does have per product options on the quantity selection.
I missed the 30 refund period by a few days, is there any chance I can get a refund on the Essential package? We are a nonprofit Parent teacher association for a middle school and we all work on the website as volunteers so the money means a lot to us.

I tried it but I don't see it working.
Maybe I didn't implement it correctly.
I assumed the Quantity file you referred to was quantity.php.

What "Field Type do you recommend I use, I tried drop-down?

I also added the PTA membership category to "Categories"

The quantity file modified is in Views with the following selection: Front end brcms_template product quantity

The mofd was inserted as follows:
<?php
/**
* @package HikaShop for Joomla!
* @version 1.5.8
* @author hikashop.com
* @copyright (C) 2010-2012 HIKARI SOFTWARE. All rights reserved.
* @license GNU/GPLv3 www.gnu.org/licenses/gpl-3.0.html
*/
defined('_JEXEC') or die('Restricted access');
?>
<?php
$this->params->set('show_quantity_field',$this->row->singlequantity);
if(!empty($this->row->has_options)){
echo $this->cart->displayButton(JText::_('CHOOSE_OPTIONS'),'choose_options',$this->params,hikashop_completeLink('product&task=show&product_id='.$this->row->product_id.$this->itemid),'window.location = \''.str_replace("'","\'",hikashop_completeLink('product&task=show&product_id='.$this->row->product_id.$this->itemid)).'\';return false;','');
}else{