I have easily published over 100 articles at ezine, and the only 3 rejections that I have received were articles that I tried to use as both content on one of my websites and as an article submission. It doesn't matter if you are the true author or not, they don't want any duplicate content whatsoever on their site. It doesn't benefit them at all, and they are constantly working to keep in good standing with the search engines.
If you want to use an article for both purposes, it is recommended that you submit it to ezine first so that it passes all their dupe content checks, and then post it to your own website. But you may still have chance to publish it on some of the lesser known article directories that don't have such strict guidelines.
Also, check to see if someone else has already grabbed your content and used it on another website. You will be surprised how fast a decent article will be swept up and used all over without any credit given to the original author. In other words, don't expect any backlinks from it.