Security Assist includes Cookies Toolkit, so you won't need to install Cookies Toolkit.
Form Builder includes Universal Email, HTML Editor, and Digital File Pro
iRite has been replaced by HTML Editor.
It seems that you have it all figured out from what I can tell.
In terms of uninstalling... I'd recommend deleting your user's Dreamweaver Configuration folder (or renaming it for a backup). This will effectively uninstall all of your extensions at once and save you quite a bit of time.
Then you can reinstall from there. Installing all of them is probably faster than uninstalling one.
In terms of the order to install you should make sure to install the most recently updated extension last and replace all shared files. The order shouldn't matter too much as long as you end with a recent one and replace all of the files. So I'd suggest installing Security Assist last and use "yes to all".