Seebz

Improve Page Permalinks. 
This plugin just adds .html to the permalink pages when needed. 
An option can prevent this action for specific pages.
<h4>Example</h4>
<ul>
<li>yourblog.com/page.html</li>
<li>yourblog.com/parent/</li>
<li>yourblog.com/parent/child.html</li>
</ul>
<h4>Compatibility</h4>
Not tested yet with all previous 3.0 WordPress version
Tests OK with the following plugins
<ul>
<li><a href="https://wordpress.org/extend/plugins/permalink-redirect/" rel="ugc">Permalink Redirect</a> (v2.0.4)</li>
<li><a href="https://wordpress.org/extend/plugins/cms-tree-page-view/" rel="ugc">CMS Tree Page View</a> (v0.6)</li>
</ul>

Improved Page Permalinks

Improve page permalinks by adding ".html" for final pages

wpyb

To prevent that usernames are publically visible, the username in the author’s permalink is replaced with the author’s ID. 
In case the page is invoked with the default permalink structure, it is displayed “Page not found”.
Additionally it is possible to modify the author base. It is recommended to make use of this plugin to change it, but it also works with other plugins that have the functionality to customize the author base.

Change Author Link Structure

To prevent that usernames are publically visible, the username in the author's permalink is replaced with the author's ID.

Improved Page Permalinks vs Change Author Link Structure