I have made a form that is dynamic in that it uses display rules for various elements.
This form will be used as an order form but i am not using the integrated payments stuff in webformbuilder. developer will do this. All images in the form will be referenced from my website so none stored in common .
user of form will get confirm.

What are the essential files I need to tell him he needs to retain.

.html file
data_validation.js
.css file
and the file that contains the phpmailer info for the confirm

anything else??? there are so many unneeded files it seems

Keep them all as if their not being used it doesn't effect your form. This way you know it will work. Otherwise do a delete and submit testing to find out.