Sandbox page
Hah, I do see the Sandbox link at the top of the page....we should definitely use that. Not sure I'm getting everything you are talking about...what is a red coat?, not on wp's disambiguation page ;). I don't have a "Sandbox" page, mine is "My_sandbox", and I noted that the link on my page is blue (seems to run counter to the usual practice). Also, not sure what the "slightly less magic functionality" is referring to, but I have to wholeheartedly agree that less magic is better.
So if I'm understanding this, my opinion would be to direct the person to use the Sandbox link at the top of the page, have the edit space be totally blank (unlike wp which has a template at the top...although I could be convinced of the wisdom of the template, if needed) and then suggest the new user type something at the top, like "Welcome to my Sandbox page", and save the page. At which point we direct them to edit using VisualEditor.
Further thoughts?
red coat being slang for a new user that has yet to populate their user page... so that links to their name (in Recent Changes, New Pages, page history, etc.) are red.
