I think you are overcomplicating it.
when eCart stores the order information, it uses an orders table for storing the order summary and an orderdetails table for storing a record for each product in the order using the eCart Store Order Details behavior.
the options are store in the cart options column separated by a <br> tag.
In the eCart Store Order Details behavior, you just need to bind the options column of the order details table to the options column of the cart