Feed Only WordPress Theme

I'm trying to create a theme which renders nothing but allows access to the feed url and the admin page. This is a continuation of this question: Make Only Accessible to Feed URL on a WordPress Site.

I've created empty style.css with the comment header as follows.

style.css

/*    Theme Name: Only Feeds    Description: Renders only feeds.    Version: 0.0.1    Template: twentyeleven*/

And created the following empty files under the theme directory.

Added Files

search.phpsearchform.phpshowcase.phpsidebar.phpsidebar-footer.phpsidebar-page.phptag.phpsingle.phpstyle.css404.phparchive.phpauthor.phpcategory.phpcomments.phpcontent.phpcontent-aside.phpcontent-featured.phpcontent-gallery.phpcontent-image.phpcontent-intro.phpcontent-link.phpcontent-page.phpcontent-quote.phpcontent-single.phpcontent-status.phpfooter.phpfunctions.phpheader.phpimage.phpindex.phppage.php

It seems to be working so far but I noticed that when I forgot to create the empty single.php, navigation text appeared in a single page. That makes me concern if I'm missing something or not.

Also if Twenty-eleven gets updated and happens to add some files, will there be a page that outputs something?