Yes. It is as I stated. Use the template to ADD content. Perhaps the users do not modify the template itself, but it would probably be better to have the template to build the document.

The users select the items that are optional, and when finished that optional content is inserted. Rather than have ALL content in the new document, and the users have to remove anything.

This certainly can be done, and by a variety of methods. The basic document, and a displayed userform to select the optional is one way.

It takes good design and well thought structure, but it is very possible. If you really want to have all the content in and do a removal route, an efficient method is to have all of the "chunks" bookmarked. Removing them is easy.