Hi,
There is no option to dynamically display the fields based on the quantity since the fields are displayed before the quantity.
What you can do however is to have only one field and remove the display of the quantity field with the option "Display the quantity field on the product page" of the HikaShop configuration.
That way, the customers will have to add the product one by one to his cart, and each time, he will be able to enter one name (and potentially one email).
That would also allow you to easily get the list of all the names and emails when exporting the orders in the backend as they will all be in one column in the CSV.