Please update us with a link when the PI 3 documentation is available. Reviewing all documentation that you linked, they all date prior to the release. I don't mind testing the beta, but I refuse to thrash just to connect via SSH.
Anyone understand the process? Point us to an alternative guide?
I completed the installation successfully!
These documents were all I needed.
I think that was everything I did to complete the setup.
If you need to start from scratch, the article on the wiki appears to be for the PI 2 and not applicable to the most recent build for the PI 3. The article linked below references "root=/dev/sda2" in the cmdline.txt file as cited for #5. There is no such entry in the file.
I will have to explore other options.
I did thrash for several minutes after creating an Ubuntu One account and adding the public SSH key. It does not happen immediately and took about five minutes for the key to propagate so I could complete the install. I am not terribly patient.