Linking my articles back to the original content on my site

I have heard all those things as well. But, I will answer your questions based my own personal experience.

I publish the post on my own blog first, wait for it to get indexed, then I simply submit it to as many directories as I can without changing anything.

I have been doing this since I started my blog last year and now I rank 1, 2, 3 for the biggest keywords in my niche (make money online, how to make money online, ways to make money).

It depend on what you want out of article marketing.
If you want to attract traffic and keep them on your site, why would you want to link from the article to the same article on your site?...
Readers would probably immediately leave your site, since they just red your artcile before clicking on your link.

If you are submitting articles only for backlinks, so you can rank higher, then it doesn't matter, of course. You can link to the same article.
I simply link from one article to a different article on my site. That way, I get both backlinks and traffic that may stay on my site longer.

You should spin the author bio, not because of any duplicate issue, but to use a verity of anchor texts.

You dont want to just link to your page using just one keyword. That wouldn't look natural to SEs. Plus, if you build backlinks using different keywords, that means you may rank for all those keywords and get traffic from all of them and not only one keyword.

You dont have to change the title, but since changing take a few seconds, why not change it!

Keep your user name (pen name) the same. Having different user names makes its a bit difficult for the directories to confirm you are the original writer of the article. I had a few of my articles deleted when I fist started, because I had them under a different pen name on other directories.

I hope this will help.