Christiaan Conover

Author Customization gives you much more flexibility in managing post and page author data. Your author data will no longer be tied solely to the WordPress user system, and can now be managed on a per-post basis. Author name and description are saved with each post, allowing you to preserve this information as it was when the post was published.
Features
<ul>
<li>Per-post author display name and biographical info</li>
<li>TinyMCE (WYSIWYG) editor for user profile and per-post biographical info</li>
<li>rel=”nofollow” link inside biographical info entries</li>
</ul>

Author Customization

Author Customization expands core author management with features such as per-post author information and rich user bio editing.

kubiq

This plugin will replace raw textarea by TinyMCE WYSIWYG editor when “Use HTML content type” is checked. 
Works for both Mail and Mail (2) in Contact Form 7.

Contact Form 7 – email body TinyMCE editor

TinyMCE WYSIWYG editor when "Use HTML content type" is checked in Contact Form 7 Mail and Mail (2)

Author Customization vs Contact Form 7 – email body TinyMCE editor