Can we take existing content as template?

It will be interesting to be able to take actual content and make a template with it. You will need the ability to transfer all used images in a special folder like folder templatethis or templatethat to be able to have a total control over the template.

Not sure what you mean...

But You can create a template with any content you want.
Content Templater places that into the editor.

But Content Templater does not control what the user does with that content after it is applied. So it does not force the user to keep that content in that form. To do that, use a package like JoomSuite Resources, SOBI or K2.

Content Templater is more to give a predefined example as content. Or to use as a quick way to call on predefined pieces of text.