That post was from a week ago - it's still relevant, for sure.
The variations should be removed - canonical is an indicator to the engines, it's not going to destroy your site if you canonical pages to themselves.
I use the Yoast Wordpress SEO plugin on all of my own/client sites, and he has the self referencing canonical there as well. I think it's just good practice to prevent the types of issues you have mentioned.
To find the links to your site with these parameters, use Open site Explorer from Moz, and also check the links mentioned in Google Webmaster Tools - it's under the traffic section in the navigation. They'll both let you download lists of external links pointing to your site, and then you can see the links that are causing these parameters.
