I think this is a good topic and you did a nice job of outlining most everything.
I do feel press releases add some value when done properly. Also, in my experience link exchanges do help just a little but only if it is relevant to the page/content/article and on a valuable page.
Doing a high quality article about other sites relevant to your overall theme can produce you free links from them, especially if they like the article and you interview them before posting it.
You covered a lot of good points and hope this helps a little.
Keep up the great work!