Nice sites Patrice :)
Ray, I may have another developer building the core for me as Its something I never done before (I have done 1 page websites before and those are easy, but this project is very different). I'm going to make sure client understands the SEO concerns, I am sure they will understand as they do realize technology constraints.
Further to my initial description, I wanted to expand on it..The background will cycle automatically (smooth fade) through other backgrounds.
One the right hand side will be a "Menu" link and when user clicks on it a side bar slides from the right (above background and with 50% translucency). when the user clicks on a link inside this side bar then the side bar closes and the content is update. Even though I am using parallax content, its not on every section of content. so for example the homepage will contain a parallax background then displaying text under it. But its not like a traditional parallax one page layout where you can keep scrolling down to see all of the websites content. This is where it differs from that.
The main concern for client is smoothness of content fading and sliding in/out they want the website to be smooth on desktop as well as mobile devices. I'm wondering if something like Adobe Edge Animate is best for this type of project rather than dreamweaver. and then for the backend use dreamweaver/webassist extensions to create the admin stuff as they want it all content managed.