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.

OrbitingWeb

When you shift your blog from HTTP to HTTPS, all your posts/pages lose facebook likes/share count. The only way to regain these likes/share counts is to add a ‘OG URL’ tag that points back to the older ‘HTTP’ urls as <a href="https://developers.facebook.com/docs/plugins/faqs#moving-urls" rel="nofollow ugc">described here by Facebook</a>.
This plugin helps you do just that.
For example, if you use a SEO plugin like Yoast, the OG URL tag automatically reflects the HTTPS version for HTTPS URLs. This plugin adds a filter to the ‘OG URL’ output and changes it back to ‘HTTP’ for all existing posts/pages. New posts that you add after this plugin is activated will not be affected.
Similary, the canonical URL tag remains unchanged as ‘HTTPS’. Canonical tag is used by search engines like Google. So you are good when it comes to SEO.
This plugin changes the OG URL output for the following popular plugins:
<ul>
<li>Yoast SEO Plugin</li>
<li>ALL In One SEO Pack</li>
<li>WP facebook open graph protocol by Chuck Reynolds</li>
<li>Facebook Open Graph, Google+ and Twitter Card Tags plugin by Webdados</li>
</ul>
<h4>Note</h4>
This plugin only changes the ‘OG URL’ tags for posts that existed when this plugin is first installed. This way all new posts will have the regular OG URL tags with ‘HTTPS’.
<h3>Steps to make this work</h3>
You need to follow these steps in order for the plugin to work:
Step 1: Install and activate the plugin.
Step 2: If you are using a Cache plugin (eg: WP Super Cache), delete the cache.
Step 3: Exclude facebook bot from the HTTP to HTTPS redirection in your HTaccess file. Here’s an example:
RewriteEngine On 
RewriteCond %{SERVER_PORT} 80 
RewriteCond %{HTTP_USER_AGENT} !facebookexternalhit/[0-9] 
RewriteRule ^(.*)$ https://sitename.com/$1 [R=301,L]
The above rewrite rule excludes facebook bots from the redirect.
Step 4: Wait for 30 days for facebook to rescrape your pages. Your ‘share count’ will return when facebook rescrapes your page.
<h3>Test to see if this works</h3>
You can instantly check to see if you did everything right by forcing facebook to rescrape one or many of your pages. Here’s how you can do that:
<ul>
<li>Login to your facebook account and go to <a href="https://developers.facebook.com/tools/debug/" rel="nofollow ugc">Facebook debugger tool</a></li>
<li>Enter the ‘HTTPS’ url of one of your pages/posts and click the ‘Debug’ button. </li>
<li>If you get the “This URL hasn’t been shared on Facebook before.” message,click on the ‘Fetch New Information’ button. </li>
<li>Now click ‘Scrap Again’. You should now be able to see all your ‘likes’ to the page. You would also see two URLs under the ‘Redirect path’ 
heading which reflects your og:url meta tag and your original HTTPS URL.</li>
</ul>
Even if you do not manually rescrape your URLs, facebook will automatically rescape your URLs within 30 days. So all your ‘share counts’ will return within 30 days.
For detailed information on these steps, <a href="https://orbitingweb.com/blog/http-to-https-retain-facebook-likes/" rel="nofollow ugc">check out this article</a>
<h3>Want any new features?</h3>
Want any new features added to this plugin? Just send me an email. <a href="https://orbitingweb.com/lets-get-in-touch/" rel="nofollow ugc">You can find my email here.</a>

Change OG URL To HTTP

Changes OG URL tag added by Yoast, Aioseo and other plugins from HTTPS to HTTP to retain facebook like count for posts and pages.

404 Simple Redirect vs Change OG URL To HTTP