Reiji Sato

Control the output log file regardless of WP_DEBUG mode. 
Specify output directory and file name, download and delete files.
And specify the date format as the file name, you can split the log every day and every month.

WP Output Log File

License: GPLv2 or later License URI: http://www.gnu.org/licenses/gpl-2.0.html This plugin can manage the output log file, specify output directory an …

JordiPlana

This plugin hooks the normal WordPress workflow in order to determine if the request is processing will cause a 404 HTTP error. In that case it prevents WordPress to do any other processing and sends the user to the page defined in the plugin options.
A working and simple solution.
For more information about this plugin you can check <a href="http://jordiplana.com/404-simple-redirect-plugin-for-wordpress" title="404 Simple Redirect Plugin for WordPress" rel="nofollow ugc">the official page</a>.

404 Simple Redirect

This plugin hooks the normal Wordpress workflow in order to determine if the request is processing will cause a 404 HTTP error.

WP Output Log File vs 404 Simple Redirect